EXHIBIT 10.1

THIS NOTE HAS NOT BEEN REGISTERED  UNDER THE SECURITIES ACT OF 1933, AS AMENDED,
OR APPLICABLE  STATE  SECURITIES  LAWS.  THIS NOTE MAY NOT BE SOLD,  OFFERED FOR
SALE,  PLEDGED  OR  HYPOTHECATED  IN THE  ABSENCE OF AN  EFFECTIVE  REGISTRATION
STATEMENT AS TO THIS NOTE UNDER SAID ACT AND APPLICABLE STATE SECURITIES LAWS OR
PURSUANT TO AN EXEMPTION FROM THE REGISTRATION  REQUIREMENTS  UNDER SAID ACT AND
ANY APPLICABLE STATE SECURITIES LAWS.

                                 PROMISSORY NOTE

$1,513,000.00                                                     April 13, 2006

       FOR VALUE RECEIVED,  Incentra Solutions,  Inc., a Nevada corporation (the
"Company") and any successor corporation to the Company,  hereby promises to pay
to the order of JOSEPH J. GRAZIANO and his assigns  (together  with his assigns,
"Payee"),  the principal  amount of One Million Five Hundred  Thirteen  Thousand
Dollars  ($1,513,000.00)  on the terms set forth below.  The Company promises to
pay interest on the principal  amount of this Note in arrears from and including
the date hereof on the principal balance from time to time outstanding, computed
daily,  at an  annual  rate  of  one-half  percent  (1/2%).  Interest  shall  be
calculated  on the basis of actual  number  of days  elapsed  over a year of 360
days.  Notwithstanding  any other provision of this Note, the holder hereof does
not intend to charge and the Company  shall not be required to pay any  interest
or other fees or charges in excess of the maximum  permitted by applicable  law;
any  payments  in excess of such  maximum  shall be  refunded  to the Company or
credited  to reduce  principal  hereunder.  The  Company  may  prepay any or all
principal  and accrued  interest due under this Note at any time,  upon ten (10)
days prior notice to holder, without penalty.

       Eight  equal  payments  of  principal  and  interest in the amount of One
Hundred  Ninety  Thousand One Hundred  Ninety and 38/100  Dollars  ($190,190.38)
shall be due and payable  without notice or demand,  the first payment being due
on July 15, 2006, and the seven remaining payments being due on the first day of
each  September,  December,  March  and June  during  the  period  beginning  on
September 1, 2006 and ending on March 1, 2008.  For purposes of this Note,  each
such date on which  payment is due shall be referred to as a "Payment Due Date".
Payments shall be made by wire transfer of immediately  available  United States
federal  funds  sent to an  account  or  accounts  designated  by the  holder in
accordance with the instructions furnished to the Company for that purpose.

       This Note  constitutes  the  "Promissory  Note" described in that certain
Stock Purchase Agreement dated April 13, 2006 (the "Stock Purchase  Agreement"),
by and among the Company,  Payee,  and Network  System  Technologies,  Inc.,  an
Illinois  corporation,  and is  entitled  to all of the  benefits  of the  Stock
Purchase  Agreement.  Unless defined herein,  capitalized terms used herein that
are defined in the Stock Purchase Agreement have the meaning given to such terms
in the Stock Purchase Agreement.




The Company agrees to pay all costs,  charges and expenses incurred by the Payee
and its assigns  (including,  without  limitation,  costs of  collection,  court
costs, and reasonable  attorneys' fees and disbursements) in connection with the
successful  enforcement  of the Payee's  rights under this Note (all such costs,
fees and expenses being herein referred to as "Costs").

       The Company hereby expressly  waives  presentment,  demand,  and protest,
notice of demand, dishonor and nonpayment of this Note, and all other notices or
demands of any kind in connection  with the delivery,  acceptance,  performance,
default or enforcement hereof. The rights and remedies of the holder as provided
herein shall be cumulative  and  concurrent  and in addition to any other rights
the  Payee  may  have  at law,  in  equity  or  otherwise,  and  may be  pursued
singularly,  successively  or together at the sole  discretion of the holder and
may be exercised as often as occasion  therefor shall occur.  The Company agrees
that any delay or failure on the part of the Payee in  exercising  any rights or
remedies  hereunder  will not  operate as a waiver of such  rights,  and further
agrees that any  payments and  prepayments  received  hereunder  will be applied
first to Costs,  then to interest and the balance to principal.  The Payee shall
not by any act, delay, omission or otherwise be deemed to have waived any of its
rights or  remedies,  and no waiver of any kind shall be valid unless in writing
and signed by the party or parties waiving such rights or remedies. All payments
under this Note  shall be made  without  counterclaim,  offset or defense of any
kind.

       This Note will be  registered on the books of the Company or its agent as
to principal and  interest.  This Note applies to, inures to the benefit of, and
binds the successors and assigns of the parties  hereto;  provided  however that
the Company shall not assign this Note without the prior written  consent of the
Payee,  which  consent may be withheld in Payee's sole and absolute  discretion.
Any  transfer of this Note by Payee will be effected  only by  surrender of this
Note to the Company and  reissuance of a new note to the  transferee.  The Payee
and any  subsequent  holder  of this Note  receives  this  Note  subject  to the
foregoing  terms and  conditions,  and agrees to comply with the foregoing terms
and conditions for the benefit of the Company and any other Payees.

       Any notice  required or permitted under this Note shall be in writing and
shall be  deemed  to have  been  given on the date of  delivery,  if  personally
delivered to the party to whom notice is to be given,  or on the third  business
day after  mailing,  if mailed  to the party to whom  notice is to be given,  by
certified mail,  return receipt  requested,  postage  prepaid,  and addressed as
follows:

       If to the Company, at

              Incentra Solutions, Inc.
              1140 Pearl Street
              Boulder, CO 80302
              Attn:  Chief Executive Officer

       If to Payee, at

              Joseph J. Graziano
              2050-80 Finley Road
              Lombard, Il 60148

                                       2



       or, in each  case,  to the most  recent  address,  specified  by  written
notice, given to the sender pursuant to this paragraph.

       If any one or more of the following  events  ("Events of Default")  shall
occur, to wit:

              (a)    Failure by the Company to make prompt payment, when due, of
       any payment due hereunder,  and such failure  continues for five (5) days
       after Payee gives written notice thereof to Company;

              (b)    The failure by Company to observe,  keep or comply with any
       provision or requirement contained in the Stock Purchase Agreement; or

              (c)    Failure by the Company to  promptly  perform or observe any
       other covenant,  promise or agreement  contained  herein and such failure
       continues for five (5) days after Payee gives written  notice  thereof to
       Company.

then,  at any time  thereafter,  at the sole  option of Payee,  without  further
notice to  Company,  the unpaid  principal  balance,  accrued  interest  and the
prepayment premium or penalty,  if any, shall become immediately due and payable
without presentment,  notice of dishonor, demand, notice or protest of any kind,
all of which  are  expressly  waived by the  Company.  All sums  coming  due and
payable under this paragraph  shall bear interest after  acceleration  hereof at
the rate of ten (10%)  percent per annum or the maximum  rate  permitted by law,
whichever is less (the "Default Rate"). In the event that any installment is not
received by Payee within ten (10) days of its due date, Company shall pay a late
charge of five (5%)  percent  ("Late  Charge") of said  installment,  which Late
Charge shall continue until all past due  installments  and accrued Late Charges
are  paid in full,  or upon the  occurrence  of an Event of  Default,  whichever
occurs first.

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

       If  any  provision  in  this  Note  is  held  by  a  court  of  competent
jurisdiction  to be in  violation  of any  applicable  local,  state or  federal
ordinance,  statute, law, administrative or judicial decision, or public policy,
and if such court should  declare  such  provision of this Note to be illegal or
unenforceable  as  written,  then such  provision  shall be given full force and
effect  to  the  fullest  possible  extent  that  (1)  it is  legal,  valid  and
enforceable,  (2) the  remainder  of this  Note  shall be  construed  as if such
illegal  or  unenforceable  provision  was not  contained  therein,  and (3) the
rights, obligations and interest of the Company and Payee under the remainder of
this Note shall continue in full force and effect.


       COMPANY  HEREBY  (A) WAIVES ANY RIGHT TO A TRIAL BY JURY IN ANY ACTION TO
ENFORCE  OR  DEFEND  ANY  MATTER  ARISING  FROM OR  RELATED  TO THIS  NOTE;  (B)
IRREVOCABLY SUBMITS TO THE JURISDICTION OF ANY STATE OR FEDERAL COURT LOCATED IN
OR NEAR CHICAGO, ILLINOIS OR BOULDER, COLORADO, OVER ANY ACTION OR PROCEEDING TO
ENFORCE OR DEFEND ANY

                                       3



MATTER ARISING FROM OR RELATED TO THIS NOTE; (C) WAIVES PERSONAL  SERVICE OF ANY
AND ALL PROCESS UPON  COMPANY,  AND CONSENTS THAT ALL SUCH SERVICE OF PROCESS BE
MADE BY MESSENGER, CERTIFIED MAIL OR REGISTERED MAIL DIRECTED TO SUCH COMPANY AT
THE ADDRESS SET FORTH ABOVE AND SERVICE SO MADE SHALL BE DEEMED TO BE  COMPLETED
UPON THE EARLIER OF ACTUAL  RECEIPT OR THE SECOND  (2ND)  BUSINESS DAY AFTER THE
SAME SHALL HAVE BEEN POSTED TO SUCH  COMPANY;  (D)  IRREVOCABLY  WAIVES,  TO THE
FULLEST  EXTENT COMPANY MAY  EFFECTIVELY  DO SO, THE DEFENSE OF AN  INCONVENIENT
FORUM TO THE MAINTENANCE OF ANY SUCH ACTION OR PROCEEDING; AND (E) AGREES NOT TO
INSTITUTE  ANY  LEGAL  ACTION  OR  PROCEEDING  AGAINST  PAYEE OR ANY OF  PAYEE'S
DIRECTORS,  OFFICERS,  EMPLOYEES,  AGENTS OR  PROPERTY,  CONCERNING  ANY  MATTER
ARISING OUT OF OR  RELATING TO THIS NOTE IN ANY COURT OTHER THAN ONES  INDICATED
ABOVE.  NOTHING IN THIS PARAGRAPH  SHALL AFFECT OR IMPAIR PAYEE'S RIGHT TO SERVE
LEGAL  PROCESS IN ANY  MANNER  PERMITTED  BY LAW OR  PAYEE'S  RIGHT TO BRING ANY
ACTION OR PROCEEDING AGAINST COMPANY, OR ANY COMPANY'S PROPERTY IN THE COURTS OF
ANY OTHER JURISDICTION.

       IN WITNESS  WHEREOF,  the Company has executed this Note under seal as of
the date first written above.

                                        INCENTRA SOLUTIONS, INC.


                                        By: /s/ Thomas P. Sweeney
                                            ---------------------
                                            Thomas P. Sweeney III
                                            Chief Executive Officer


                                       4