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                                 EXHIBIT 10 (xx)

                     FIRST AMENDMENT TO 1996, 1997 AND 1998
                           OFFICER MANAGER BONUS PLAN

  This First  Amendment to each of the CDW 1996 Officer and Manager Bonus
Plan,  CDW  1997  Officer  and  Manager  Bonus  Plan and CDW  1998  Officer  and
Management Bonus Plan is made as of this 5th day of April, 1999 with effect from
July 23, 1999.

                              W I T N E S S E T H:

         WHEREAS,  on December 31 of each of 1996,  1997 and 1998,  CDW Computer
Centers,  Inc., an Illinois  corporation (the  "Company"),  adopted the CDW 1996
Officer and Manager  Bonus Plan,  1997  Officer and Manager  Bonus Plan and 1998
Officer and Manager Bonus Plan,  respectively (each a "Plan" and,  collectively,
the  "Plans"),  pursuant  to  which  the  Company,  as  designated  by  the  CDW
Compensation  and Stock Option  Committee  (the  "Committee"),  is authorized to
grant  bonuses  to  management  personnel  for the  year in  which  the Plan was
implemented;

         WHEREAS, the  Committee  deems it to  be in  the best interests of  the
Company that the Plans be amended as reflected herein; and

         WHEREAS,  the  Committee  is vested  with the ability to amend the Plan
pursuant to Section 3 thereof.

         NOW,  THEREFORE,  in accordance with the powers vested in the Committee
under the Plans, the Plans shall each be amended as follows:

1. The first sentence of Section 5 shall be deleted in its entirety.

         2. The  heading in  Section  5 shall be restated  as  follows:  "Death,
Disability or Retirement."

         3. Section 5 shall be amended by restating the existing  subsection (c)
as subsection (d) thereof and by adding the following as the new subsection (c):

                  "(c) if  cessation  of  employment  occurs  by  reason  of the
                  Retirement  (as  hereinafter  defined)  of  the  Participating
                  Employee,  the options granted to such Participating  Employee
                  shall  continue  to vest in  accordance  with  their  original
                  vesting  schedule  and the  Participating  Employee  shall  be
                  entitled  to  exercise  said  options as if the  Participating
                  Employee were still employed by the Company."

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         4. A new subsection 5(e) shall be added as follows::

                  "(e)  "Retirement"  for purposes of this Plan shall be defined
                  as   the   voluntary   termination   of   employment   by  the
                  Participating  Employee at any time after attaining age 62 and
                  provided   that   said   Participating   Employee   has   been
                  continuously  employed by the Company for a period of not less
                  than  ten  (10)  years  at  the  time  of  the   Participating
                  Employee's voluntary termination."

         5. This  Amendment  shall be  incorporated  into and made a part of the
Plan.

         6. All terms and provisions of the Plan,  except as expressly  modified
herein,  shall continue in full force and effect, and the parties hereby confirm
each and every one of their obligations under the Plan as amended herein.

         7. This Amendment shall be governed by and construed in accordance with
the internal laws of the State of Illinois.

         IN WITNESS WHEREOF,  the undersigned have executed this First Amendment
to the 1996 Officer and Manager Bonus Plan,  1997 Officer and Manager Bonus Plan
and 1998 Officer and Manager  Bonus Plan as of this 5th day of April,  1999,  in
Vernon Hills, State of Illinois.



                  Signature                               Title
                  ---------                               -----


         ____________________                    Director and Member of 
         Michelle L. Collins                     Compensation  and  Stock Option
                                                 Committee

         ____________________                    Director  and  Member  of  
         Joseph Levy Jr.                         Compensation  and  Stock Option
                                                 Committee