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                                 EXHIBIT 10 (mm)

                       REVOLVING NOTE BETWEEN THE COMPANY
                            AND LASALLE NATIONAL BANK
                               DATED JUNE 29, 1997

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                           REPLACEMENT REVOLVING NOTE

$15,000,000                                           Dated as of June 29, 1997
                                                            Due:  June 28, 1998


         On  or  before  June  28,  1998,  CDW  COMPUTER   CENTERS,   INC.  (The
"Undersigned"),  for value  received,  promise  to pay to the  order of  LASALLE
NATIONAL BANK, a national banking  association  (hereinafter,  together with any
holder thereof, called "Bank"), whose address is 135 S. LaSalle Street, Chicago,
Illinois  60603,  the  principle  sum of  Fifteen  Million  and  00/100  Dollars
($15,000,000)  or if less, the aggregate  unpaid  principle  amount of all loans
made  by the  Bank  to the  Undersigned  hereunder  (this  "Note").  The  unpaid
principle amount hereof shall bear interest at the  Undersigned's  option of the
following:

         (i)  a  fixed  rate  equal  to the  greater  of (A)  the  "Prime  Rate"
              (hereinafter  defined)  minus two and  one-half of one percent (-2
              1/2%) per annum,  or (B) the  "Federal  Funds  Rate"  (hereinafter
              defined)  plus  one-half  of one percent  (+1/2%)  per annum,  for
              borrowing not to exceed thirty (30) days, such rate to be fixed at
              the  beginning  of the term of such  borrowing  (the "Fixed  Prime
              Rate'); or

         (ii) a floating  rate equal to the  greater of (A) the Prime Rate minus
              two and  one-half  percent (-2 1/2%) per annum,  for  borrowing in
              excess  of  thirty  (30) days (the  "Floating  Prime  Rate");  the
              Floating  Prime  Rate and the Fixed  Prime  Rate are  referred  to
              herein collectively as the "Prime Rate"); or

         (iii)      "Adjusted LIBOR" (hereinafter defined).

         1.    For purposes hereof the following terms shall have the following
               definitions:

         "Prime  Rate" shall mean the rate in effect from time to time as set by
the Bank and called its Prime  Rate.  The  effective  date of any change in said
Prime  Rate  shall for  purposes  hereof be the date the rate is  changed by the
Bank.  The Bank shall not be obligated to give notice of any change in the Prime
Rate.

         "Federal  Funds  Rate"  shall mean,  for any day,  the daily  effective
Federal Funds rate for such day as published in the Federal Reserve  Statistical
Release H.15  ("H.15")  (or, if such  Release is not  published,  the  successor
thereto or closest  approximation  thereto,  as determined by the Bank) for such
day;  provided  that,  the  Federal  Funds Rate for any day on which the Federal
Reserve Bank of New York, (the "New York Fed") is not open for business shall be
the Federal Funds Rate for the next  preceding day on which the New York Fed was
open for business; and provided,  further, that if the Bank determines,  in good
faith,  that it is unable to  determine  the Federal  Funds Rate on the basis of
H.15,  then the  Bank  shall  determine  the  Federal  Funds  Rate  based on the
quotation of three (3) dealers in Federal  Funds in New York City, as reasonably
selected by the Bank, and the Bank's determination of such rate shall be binding
and conclusive absent manifest error.

         "Adjusted  LIBOR"  means a rate of  interest  equal to  one-half of one
percent  (1/2%) per annum in excess of the per annum rate of  interest  at which
U.S.  dollar  deposits  in an amount  comparable  to the amount of the  relevant
"LIBOR  Loan"  (hereinafter  defined)  and for a period  equal  to the  relevant
"Interest  Period"  (hereinafter  defined)  are  offered  generally  to the Bank
(rounded  upward,  if  necessary,  to the  nearest  1/16 of 1.00%) in the London
Interbank  Eurodollar  market at 11:00 a.m.  (London  time) two (2) banking days
prior to the commencement of each Interest Period, such rate to remain fixed for
such Interest Period.

         "Interest Period" shall mean successive one, two or three-month periods
as selected from time to time by the Undersigned by notice given to the Bank not
less than  three (3)  business  days  prior to the first day of each  respective
Interest  Period;  provided  that:  (i) each such one, two,  three-month  period
occurring  after such initial period shall commence on the day on which the next
preceding period expires;  (ii) the final Interest Period shall be such that its
expiration  occurs on or before the stated  maturity date of the Note; and (iii)
if for any reason the  Undersigned  shall fail to select  timely a period,  then
shall be  deemed to have  selected  a LIBOR  Loan with a one (1) month  Interest
Period; provided that, at any time any Interest Period expires less than one (1)
month before the maturity date of the Note,  then, for the period  commencing on
such  expiration  date and  ending on the  maturity  date such  LIBOR Loan shall
convert to a loan bearing interest at the Floating Prime Rate.

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         2.   Interest  on that  portion  of the  outstanding  principle  amount
              hereof  bearing  interest at the Prime Rate shall be payable  from
              the date hereof on such aggregate  unpaid  principle amount on the
              last  day of each  month,  commencing  on July  31,  1997,  and at
              maturity  hereof.  Interest on LIBOR borrowing shall be payable at
              the  end  of  each  respective  Interest  Period.  Interest  after
              maturity (whether by reason of acceleration or otherwise) shall be
              paid on the unpaid  balance at the rate of the Floating Prime Rate
              plus two percent  (2%) per annum (the  "Default  Rate").  Interest
              shall be  computed on the basis of a year  consisting  of 360 days
              and shall be paid for the actual  number of days  elapsed,  unless
              otherwise specified herein.

         3.   Each LIBOR borrowing  hereunder  (each, a "LIBOR Loan") must equal
              $100,000 or an integral multiple  thereof.  Interest on each LIBOR
              Loan  shall be payable on the last  banking  day of each  Interest
              Period with respect thereto,  commencing on the first such date to
              occur  after the date  hereof,  at  maturity,  after  maturity  on
              demand,  and on the date of any payment hereon on the amount paid.
              The Undersigned hereby further promises to pay to the order of the
              Bank, on demand,  interest on the unpaid  principle  amount hereof
              after  maturity  (whether by  acceleration  or  otherwise)  at the
              Default Rate.

         4.   Provisions applicable to LIBOR Loans:(a) The Bank's determination
              of Adjusted LIBOR as provided above shall be conclusive, absent 
              manifest error.  Furthermore, if the Bank determines, in good 
              faith (which determination shall be conclusive, absent manifest 
              error), prior to the commencement of any Interest Period that (a) 
              U.S. dollar deposit of sufficient amount and maturity for funding 
              any LIBOR Loans are not available to the Bank in the London 
              Interbank Eurodollar market in the ordinary course of business, or
              (b) by reason of circumstances affecting the London Interbank
              Eurodollar market, adequate and fair means do not exist for 
              ascertaining the rate of interest to be applicable to the relevant
              LIBOR Loan, the Bank shall promptly notify the Undersigned and 
              such LIBOR shall automatically convert on the day of its 
              then-current Interest Period to a loan bearing interest at the 
              Floating Prime Rate.

         (b)  If, after the date hereof,  the  introduction of, or any change in
              any applicable law,  treaty,  rule,  regulation or guideline or in
              the  interpretation  or  administration  thereof by any government
              authority or any central bank or other  fiscal,  monetary or other
              authority having jurisdiction over the Bank or its lending offices
              (a "Regulatory  Change"),  shall, in the opinion of counsel to the
              Bank, makes it unlawful for the Bank to make or maintain any LIBOR
              Loan evidenced  hereby,  then the Bank shall  promptly  notify the
              Undersigned and such LIBOR Loan shall automatically convert on the
              last day of its  then-current  Interest  Period to a loan  bearing
              interest at the Floating Prime Rate.

         (c)  If,  for any  reason,  any  LIBOR  Loan is paid  prior to the last
              business day of its then-current  Interest Period, the Undersigned
              agrees to indemnify the Bank against any loss  (including any loss
              on redeployment of the funds repaid),  cost or expense incurred by
              the Bank as a result of such prepayment.

         (d)  If any Regulatory Change (whether or not having the force of law) 
              shall (a) impose, modify or deem applicable any assessment, 
              reserve, special deposit or similar requirement against assets 
              held by, or deposited in or for the account of or loans by, or any
              other acquisition of funds or disbursements by, the Bank: (b) 
              subject the Bank or any LIBOR Loan to any tax, duty, charge, stamp
              tax, or fee or change the basis of taxation of payment to the Bank
              principle or interest due from the Undersigned to the Bank 
              hereunder (other than a change in taxation of the overall net 
              income of the Bank); or (c) impose on the Bank any other 
              conditions regarding such LIBOR Loan or the Bank's funding 
              thereof, and the Bank shall determine (which determination shall 
              be conclusive, absent manifest error) that the result of the 
              forgoing is to increase the cost to the Bank of making or 
              maintaining such LIBOR Loan or to reduce the amount of principle 
              or interest received by the Bank hereunder, then the Undersigned 

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              shall pay to the Bank, on demand and presentation of satisfactory
              documentation therefor, such additional amounts as the Bank shall,
              from time to time, determine are sufficient to compensate and 
              indemnify the Bank for such increased cost or reduced amount.

         5.   The Undersigned  hereby  authorizes the Bank to charge any account
              of the Undersigned for all sums due hereunder.  Principle payments
              submitted in funds not available until collected shall continue to
              bear interest until collected.  If payment  hereunder  becomes due
              and payable on a Saturday,  Sunday or legal  holiday under the law
              of the  United  States  or the  State  of  Illinois,  the due date
              thereof shall be extended to the next succeeding business day, and
              interest  shall be payable  thereon at the rate  specified  during
              such extension.

         6.   The Note evidences a revolving line of credit under which the 
              Undersigned is indebted to the Bank and evidences the aggregate 
              unpaid principle amount of all advances made or to be made by the
              Bank to the Undersigned under the Note.  All advances and 
              repayments hereunder shall be evidenced by entries on the books 
              and records of the Bank which shall be presumptive evidence of the
              principle amount and interest owing and unpaid on this Note, or 
              any renewal or extension hereof.  The failure to so record any 
              such amount or any error so recording any such amount shall not, 
              however, limit or otherwise affect the obligations of the 
              Undersigned hereunder or under any not to repay the principle 
              amount of the liabilities together with all interest accruing 
              thereon.  This Note may be used for direct advances or letter of
              credit.  Each letter of credit requested by the Undersigned shall 
              be subject to the terms and conditions of the Bank's standard 
              letter of credit application, which application is incorporated 
              herein by this reference.  The amount available to the 
              Undersigned under this Note shall be reduced by the face amount of
              all letters of credit issued and outstanding hereunder.  All 
              letters of credit issued hereunder shall have an expiry date no 
              later than the maturity date of this Note.  The Undersigned and 
              the Bank agree that each draw under any letter of credit shall 
              constitute, and shall be repaid by, a direct advance under this 
              Note on the date of such draw.  Each letter of credit requested by
              the Undersigned hereunder shall be issued by the Bank only after 
              the Bank has received a fully executed letter of credit 
              application on the Bank's standard form and the Bank's customary 
              fee for issuance of letters of credit.

         7.   Advances  under this Note may be made by the Bank upon the written
              request  of any two (2)  authorized  officers  of the  Undersigned
              whose  authority to so act has not been revoked by the Undersigned
              in writing  theretofore  received by the Bank at its main  office.
              Any such advances shall be conclusively presumed to have been made
              by the  Bank  to or  for  the  benefit  of  the  Undersigned.  The
              Undersigned does hereby  irrevocably  confirm,  ratify and approve
              all such  advances by the Bank and does hereby  indemnify the Bank
              against  loss  and  reasonable  expense  (including  court  costs,
              attorneys' and paralegals'  fees) and shall hold the Bank harmless
              with respect thereto.

         8.   The Undersigned shall be in default hereunder if: (a) any amount 
              payable on this and any and all other liabilities or obligations
              of the Undersigned to the Bank, howsoever created, arising or 
              evidenced, whether now existing or hereafter arising, whether now 
              due or to become due, whether direct, indirect, absolute, 
              contingent, joint, several, or joint and several (all such 
              liabilities and obligations, including this Note, are hereinafter 
              referred to as the "Obligations") or on the obligations of any 
              obligor hereunder, it not paid within five (5) days or when due; 
              or (b) the Undersigned shall otherwise fail to perform any of the
              promises to be performed by the Undersigned hereunder or under any
              other security agreement or other agreement with the Bank and the 

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              same is not cured within thirty (30) days of notice thereof by the
              Bank; or (c) the Undersigned, or any other party liable with 
              respect to the Obligations, or any guarantor or accommodation 
              endorser or third party pledgor, shall make any assignment for the
              benefit of creditors, or there shall be commenced any bankruptcy, 
              receivership, insolvency, reorganization, dissolution or 
              liquidation proceedings by or against, or the entry of any 
              judgment, levy, garnishment, or other process (except for any 
              judgment, levy, attachment, garnishment or other process entered 
              pursuant to certain litigation instituted by John Marks, as 
              described in the Undersigned's 1997 proxy statement, as amended 
              from time to time), or the filing of any lien against the 
              Undersigned or any guarantor, or any other party liable with 
              respect to the Obligations, or accommodations endorser or third 
              party pledgor for any of the Obligations which has a material
              adverse effect on such party; or (d) the determination by the Bank
              that a material adverse change has occurred in the financial 
              condition of the Undersigned from the condition set forth in the 
              most recent financial statements of the Undersigned furnished to 
              the Bank, or from the financial condition of the Undersigned most 
              recently disclosed to the Bank in any matter and the same is not 
              cured within thirty (30) days of notice thereof by the Bank; or 
              (e) any oral or written warranty, representation, certificate or 
              statement of the Undersigned to the Bank is untrue in any material
              respect; or (f) failure of the Undersigned, within thirty (30) 
              days after a request by the Bank, to furnish financial information
              or to permit inspection by the Bank of the Undersigned's books and
              records; or (g) the occurrence of any material adverse event which
              causes a change in the financial condition of the Undersigned, or 
              which would have a material adverse effect on the business of the 
              Undersigned and the same is not cured within thirty (30) days 
              notice thereof by the Bank; provided, that any event relation to 
              the John Marks litigation as set forth in subsection (3) above 
              shall not be deemed to violate this subsection (g); or (h) the 
              Undersigned fails to have, at the end of each of its fiscal 
              quarters (1) a Tangible Net Worth of at least $35,000,000 or (2) a
              ratio of Liabilities to Tangible Net Worth of no greater than 
              2.0:1.0 and a default of either  (1) or (2) shall not be cured by
              the Undersigned within thirty (30) days.

         9.   For purpose  hereof,  "Tangible  Net Worth"  shall mean the sum of
              shareholders'  equity plus debt  subordinated  to the  Undersigned
              liabilities to the Bank,  minus  intangibles,  including,  but not
              limited to,  goodwill,  customer  lists,  prepaid items,  deferred
              charges,  debts owed by  officers  and other  affiliates  and such
              "Other  Assets" as set forth on the  financial  statements  of the
              Undersigned,  "Liabilities"  shall  mean  all  liabilities  of the
              Undersigned  that  would  be  shown  on a  balance  sheet  of  the
              Undersigned   prepared  in  accordance  with  generally   accepted
              accounting principles consistently applied.

         10.  Whenever the Undersigned shall be in default as aforesaid, without
              demand or notice of any kind except as set forth herein, the 
              entire unpaid amount of all Obligations shall become immediately 
              due and payable, and the Bank may exercise, from time to time, any
              and all rights and remedies available to it under the Uniform 
              Commercial Code of Illinois, or otherwise, including those 
              available under any written instrument (in addition to this Note) 
              relating to any of the Obligations and may, without demand or 
              notice of any kind, appropriate and apply toward the payment of 
              such of the Obligations, whether matured or unmatured including 
              reasonable costs of collections and reasonable attorneys' and
              paralegals' fees, and in such order of application as the Bank 
              may, from time to time, elect, balance, credits, deposits, 
              accounts or monies of the undersigned in possession, control or 
              custody of, or in transit of the Bank.

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         11.  THE UNDERSIGNED WAIVES THE BENEFIT OF ANY LAW THAT WOULD OTHERWISE
              RESTRICT OR LIMIT THE BANK IN THE EXERCISE OF ITS RIGHTS, WHICH 
              HEREBY ACKNOWLEDGED, TO APPROPRIATE WITHOUT NOTICE, AT ANY TIME 
              HEREAFTER, ANY INDEBTNESS MATURED OR UNMATURED, OWING FROM THE 
              BANK TO THE UNDERSIGNED.  THE BANK MAY, FROM TIME TO TIME, WITHOUT
              DEMAND OR NOTICE OF ANY KIND, APPROPRIATE AND APPLY TOWARD THE 
              PAYMENT OF SUCH OF THE OBLIGATIONS, AND IN SUCH ORDER OF 
              APPLICATION, AS THE BANK MAY, FROM TIME TO TIME, ELECT ANY AND ALL
              SUCH BALANCE, CREDITS, DEPOSITS, ACCOUNTS, MONIES, CASH 
              EQUIVALENTS AND OTHER ASSETS OF OR IN THE NAME OF THE UNDERSIGNED,
              THEN OR THEREAFTER WITH THE BANK.  THE UNDERSIGNED DOES HEREBY 
              ASSIGN AND TRANSFER TO THE BANK ANY AND ALL CASH, NEGOTIABLE 
              INSTRUMENTS, DOCUMENTS OF TITLE, CHATTEL PAPER, SECURITIES,
              CERTIFICATES OF DEPOSIT, DEPOSIT ACCOUNTS, OTHER CASH EQUIVALENTS 
              AND OTHER ASSETS OF THE UNDERSIGNED IN THE POSSESSION OR CONTROL 
              OF THE BANK FOR ANY PURPOSE.

         12.  THE UNDERSIGNED WAIVES EVERY DEFENSE, CAUSE OF ACTION, 
              COUNTERCLAIM OR SET OFF WHICH THE UNDERSIGNED MAY NOT HAVE OR
              HEREAFTER MAY HAVE TO ANY ACTION BY BANK IN ENFORCING THIS NOT OR
              ANY OF THE OTHER OBLIGATIONS, RATIFIES AND CONFIRMS WHATEVER THE 
              BANK MAY DO PURSUANT TO THE TERMS HEREOF AND AGREES THAT THE BANK 
              SHALL NOT BE LIABLE FOR ANY ERROR OF JUDGEMENT OR MISTAKE OF FACT 
              OR LAW EXCEPT FOR THOSE ERRORS OR MISTAKES WHICH RESULT FROM THE 
              BANK'S GROSS NEGLIGENCE OR WILLFUL MISCONDUCT.  THE BANK AND THE 
              UNDERSIGNED, KNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVE 
              IRREVOCABLY THE RIGHT EITHER MAY HAVE TO TRAIL BY JURY WITH 
              RESPECT TO ANY LEGAL PROCEEDING BASED HEREON, OR ARISING OUT OF, 
              UNDER OR IN CONNECTION WITH THIS NOTE OR ANY OF THE OTHER 
              OBLIGATIONS, OR ANY AGREEMENT, EXECUTED OR CONTEMPLATED TO BE 
              EXECUTED IN CONJUNCTION HEREWITH OR ANY COURSE OF CONDUCT OR 
              COURSE OF DEALING IN WHICH THE BANK AND THE UNDERSIGNED ARE 
              ADVERSE PARTIES.  THIS PROVISION IS A MATERIAL INDUCEMENT FOR THE
              BANK GRANTING ANY FINANCIAL ACCOMMODATIONS TO THE UNDERSIGNED.


         13.  The Undersigned, and any other party liable with respect to the 
              Obligations, including any guarantors, and any and all endorsers 
              and accommodation parties, and each one of them, waive any and all
              presentment, demand, notice of dishonor, protest, and all other 
              notices and demands in connection with the enforcement of the 
              Bank's right hereunder, and hereby consent to, and waive notice of
              release, with or without consideration, of the Undersigned.  No 
              default shall be waived by the Bank except in writing.  No delay 
              on the part of the Bank in the exercise of any right or remedy 
              shall operate as a waiver thereof, and no single or partial 
              exercise by the bank of any right or remedy shall preclude other 
              or further exercise thereof, or the exercise of any other right or
              remedy.  This Note: (i) is valid, binding and enforceable in
              accordance with its provisions, and no conditions exist to the 
              legal effectiveness of this Note; (ii) contains the entire 
              agreement between the Undersigned and the Bank; (iii) is the final
              expression of the intention of the Undersigned and the Bank; and 
              (iv) superseded all negotiations, representations, warranties, 
              commitments, offers, contracts (of any kind of nature, whether 
              oral or written) prior to or contemporaneous with the execution 
              hereof.  No prior or contemporaneous representation, warranties, 
              understandings, offers or agreements of any kind or nature, 
              whether oral or written, have been made by the Bank or relied upon
              by the Undersigned is connection with the execution hereof.  No
              modifications, discharge, termination or waiver of any of the 
              provisions hereof shall be binding upon the Bank, except as 
              expressly set forth in a writing duly signed and delivered on 
              behalf of the Bank.

         14.  The  Undersigned   agrees  to  pay  all  reasonable  costs,  legal
              expenses, attorneys' fees and paralegals' fees of every kind, paid
              or  incurred  by the  Bank  in  enforcing  its  rights  hereunder,
              including, but not limited to, litigation or proceedings initiated
              under the  United  States  Bankruptcy  Code,  or in respect to any
              other of the  Obligations,  or in  defending  against any defense,
              cause of action, counterclaim,  set off or crossclaim based on any
              act of  commission  or omission  by the Bank with  respect to this
              Note or any other of the  Obligations,  promptly  on demand of the
              Bank or other person paying or incurring the same.

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         15.  TO INDUCE THE BANK TO MAKE THE LOAN EVIDENCED BY THIS NOTE, THE 
              UNDERSIGNED IRREVOCABLY AGREES THAT ALL ACTIONS ARISING DIRECTLY 
              OR INDIRECTLY AS A RESULT OR IN CONSEQUENCE OF THIS NOTE OR ANY 
              OTHER AGREEMENT WITH THE BANK SHALL BE INSTITUTED AND LITIGATION 
              ONLY IN COURTS HAVING SITUS IN THE CITY OF CHICAGO, ILLINOIS, AND 
              THE UNDERSIGNED HEREBY CONSENTS TO THE EXCLUSIVE JURISDICTION AND 
              VENUE OF ANY STATE OR FEDERAL COURT LOCATED AND HAVING ITS SITUS 
              IN SAID CITY, AND WAIVES ANY OBJECTION BASED ON FORUM NON 
              CONVENIENS.  THE UNDERSIGNED HEREBY WAIVES PERSONAL SERVICE OF ANY
              AND ALL PROCESS, AND CONSENTS THAT ALL SUCH SERVICE OF PROCESS MAY
              BE MADE BY CERTIFIED MAIL, RETURN RECEIPT REQUESTED, DIRECTED TO 
              THE UNDERSIGNED AT THE ADDRESS INDICATED IN THE BANK'S RECORDS IN 
              THE MANNER PROVIDED BY APPLICABLE STATUTE, LAW, RULE OF COURT OF 
              OTHERWISE.

         16.  The loan evidenced hereby has been made and this Note has been 
              delivered at the Bank's main office.  This Note shall be governed
              and construed in accordance with the laws of the State of 
              Illinois, in which state it shall be performed, and shall be 
              binding upon the Undersigned and its successors and assigns.  If 
              this Note contains any blanks when executed by the Undersigned, 
              the Bank is hereby authorized, without notice to the Undersigned, 
              to complete any such blanks according to the terms upon which the 
              loan or loans were granted.  Wherever possible, each provision of 
              the Note shall be interpreted in such manner as to be effective 
              and valid under applicable law, but if any provision of this Note 
              shall be prohibited by or be invalid under such law, such 
              provision shall be severable, and be deemed ineffective to the 
              extent of such prohibition or invalidity without invalidating the 
              remaining provisions of this Note.  If more than one party shall 
              execute this Note, the term "Undersigned" as used herein shall 
              mean all parties signed this Note and their respective successors 
              and assigns, and such parties shall, as the case may be, be 
              jointly and severally obligated hereunder.

         17.  The  Undersigned  represents  and  warrants  to the Bank  that the
              execution  and delivery of this Note has been duly  authorized  by
              resolution  heretofore  adopted by its Board of  Directors  and in
              accordance with law and its bylaws,  that said resolution have not
              been  amended or  rescinded  are in full force and effect and that
              the officer or officers executing and delivering this Note for and
              on behalf of the  Undersigned  are duly  authorized so to act. The
              Bank, in extending financial accommodations to the Undersigned, is
              expressly  acting and relying upon the  aforesaid  representations
              and warranties.

         18.  The   undersigned   acknowledges   and  agrees  that  the  lending
              relationship  hereby  created  with  the  Bank  is  and  has  been
              conducted  on an open and arm's length basis in which no fiduciary
              relationship exists and that the Undersigned has not relied and is
              not relying on any such fiduciary relationship in consummating the
              loan evidence by this Note.

         19.  As used  herein,  all  provisions  shall  include  the  masculine,
              feminine,  neuter,  singular  and  plural  thereof,  wherever  the
              context and facts require such  construction and in particular the
              word "Undersigned" shall be so construed.

         20.  This  Note  is in  replacement  and  substitution  for,  but not a
              repayment of, that certain  $15,000,000  Revolving Note dated June
              30, 1996 of the  Undersigned  payable to the order of the Bank and
              does  not  and  shall  not be  deemed  to  constitute  a  novation
              therefor.

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         IN WITNESS WHEREOF,  the Undersigned has executed this Note on the date
above set forth.


                                               CDW COMPUTER CENTERS, INC.


                                               By /s/ Michael P. Krasny
                                                  ---------------------
                                               Name: Michael P. Krasny
                                               Title: Chairman & Chief Executive
                                                      Officer


                                                By /s/ Harry J. Harczak, Jr.
                                                   -------------------------
                                                Name: Harry J. Harczak, Jr.
                                                Title: Chief Financial Officer



HJM:mm
July 14, 1997

67315-1

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