Document:

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                                                                   Exhibit 10.50

                             SECURED PROMISSORY NOTE

                                October 16, 2000

$26,167.89                                       Westboro, Massachusetts

      For value received, Anthony Bellantuoni (the "Borrower") promises to pay
to the order of ePresence Inc., a Massachusetts corporation (the "Company"), at
the offices of the Company or such other place as the Company hereafter shall
designate Twenty-Six Thousand One Hundred Sixty-Seven Dollars and Eighty-Nine
Cents ($26,167.89) to satisfy his federal and state tax obligations with respect
to the vesting of 12,000 shares of restricted stock of the Company (the
"Shares"), pursuant to the Executive Officer Restricted Stock Agreement dated
October 16, 1998 (the "Agreement"), in which a total of 30,000 restricted shares
of common stock of the Company were issued and sold to the Borrower. Interest
shall accrue on a daily basis on the unpaid principal balance from time to time
outstanding at the rate of prime less 1% per annum, beginning on the date that
first appears above. The principal and all accrued interest of this Note shall
be repaid in full on January 16, 2002. This Note shall immediately become due
and payable in full, as provided below.

      The Borrower acknowledges that this Note must be repaid in full prior to
the due date, upon the sale by the Borrower of any of the Shares.

      Payment of this Note is secured by a security interest in the Shares,
pursuant to a pledge agreement of even date herewith between the Company and the
Borrower (the "Pledge Agreement"). This Note is recourse to the Borrower for the
entire principal sum borrowed, plus interest, and is subject to, and secured by,
and entitled to the benefits of the Pledge Agreement.

      At the option of the Company, this Note shall become immediately due and
payable without notice or demand upon the occurrence at any time of any of the
following events ("Events of Default"):

      (1)   Borrower's voluntary termination of his employment with the Company
            for any reason prior to the repayment in full of the principal and
            any accrued interest due and payable on this Note; or

      (2)   If Borrower is not paying his debts as they become due, becomes
            insolvent, files or has filed against him a petition under any
            chapter of the United States Bankruptcy Code, 11 U.S.C. ss. 101 et
            seq. (or any similar petition under any insolvency law of any
            jurisdiction), proposes any liquidation, composition or financial
            reorganization with his creditors, makes an assignment or trust
            mortgage for the benefit of creditors, or if a receiver, trustee,
            custodian or similar agent is appointed or takes possession with
            respect to any property or business of the Borrower; or

      (3)   The occurrence of any Default (as defined therein) under the Pledge
            Agreement.

      Upon the occurrence of any of the Events of Default, the Company shall
have then, or at any time thereafter, all of the rights and remedies afforded by
the Uniform Commercial Code as from

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time to time in effect in the Commonwealth of Massachusetts or afforded by other
applicable law or under this Note or the Pledge Agreement.

      Upon the involuntary termination of Borrower by the Company prior to the
repayment in full of the principal amount and any accrued interest due and
payable on this Note, Borrower shall have 90 days from the date of such
termination to repay the principal and any accrued interest under this Note.

      In no event shall any interest charged, collected or reserved under this
Note exceed the maximum rate then permitted by applicable law and if any such
payment is paid by the holder such payment shall be treated as a payment of
principal.

      All payments by the Borrower under this Note shall be made without set-off
or counterclaim and shall be free and clear and without deduction or withholding
for any taxes or fees of any nature whatever, unless the obligation to make such
deduction or withholding is imposed by law. The Borrower shall pay and save the
holder harmless from all liabilities with respect to or resulting from any delay
or omission to make any such deduction or withholding required by law.

      Whenever any amount is paid under this Note, all or part of the amount
paid may be applied to principal, interest, premium or interest in such order
and manner as shall be determined by the holder in its discretion.

      No reference in this Note to any other document shall impair the
obligation of the Borrower, which is absolute and unconditional, to pay all
amounts under this Note strictly in accordance with the terms of this Note.

      No delay or omission on the part of the Company in exercising any right
hereunder shall operate as a waiver of such right or of any other right of such
Company, nor shall any delay, omission or waiver on any one occasion be deemed a
bar to or waiver of the same or any other right on any future occasion.

      The Borrower waives presentment, demand, notice, protest and all other
demands and notices in connection with the delivery, acceptance, performance,
default or enforcement hereof and also waives any delay on the part of the
Company. No discharge or release of any other party primarily or secondarily
liable hereon shall discharge or otherwise affect the liability of the Borrower
to the Company.

      None of the terms or provisions of this Note may be excluded, modified, or
amended except by a written instrument duly executed on behalf of the Borrower
expressly referring hereto and setting forth the provision so excluded, modified
or amended.

      The Borrower will pay on demand all costs of collection, including
reasonable attorney's fees, incurred by the Company in enforcing the obligations
under or in connection with this Note or the Pledge Agreement.

      This Note shall be binding upon the Borrower and each endorser and
guarantor hereof and upon their heirs, successors and representatives, and shall
inure to the benefit of the Company and its successors, endorsees and assigns.

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      This Note may be prepaid in whole or in part at any time or from time to
time with the consent of the holder, with the giving of such consent to be in
the sole discretion of the holder, provided that the Company shall retain the
security interest in the Shares under the Pledge Agreement until the principal
amount and accrued interest under this Note are paid in full. Any prepayment
shall be without premium or penalty.

      The Borrower irrevocably submits to the jurisdiction of the courts of the
Commonwealth of Massachusetts and the United States District Court for the
District of Massachusetts for the purpose of any suit, action or other
proceeding brought by the Company arising out of or relating to this Agreement,
and the Borrower waives and agrees not to assert by way of motion, as a defense
or otherwise in any such suit, action or proceeding, any claim that the Borrower
is not personally subject to the jurisdiction of the courts of the Commonwealth
of Massachusetts or the United States District Court for the District of
Massachusetts or that the Borrower's property is exempt or immune from execution
or attachment, either prior to judgment or in aid of execution, that the suit,
action or proceeding is brought in an inconvenient forum or that the venue of
the suit, action or proceeding is improper, or that this Note or the subject
matter hereof may not be enforced in or by such court.

      This Note shall be governed by, and construed and enforced in accordance
with, the substantive laws of the Commonwealth of Massachusetts, without regard
to its principles of conflicts of laws. This Note shall be deemed to be under
seal.

THE PLEDGOR HEREBY WAIVES ANY AND ALL RIGHTS TO A TRIAL BY JURY IN ANY ACTION OR
PROCEEDING IN CONNECTION WITH ALL MATTERS CONTEMPLATED HEREBY AND DOCUMENTS
EXECUTED IN CONNECTION HEREWITH.

WITNESS:                                  BORROWER:

Signed in my Presence:

/s/ Richard M. Spaulding                  /s/ Anthony J. Bellantuoni
-------------------------------------     -------------------------------------
[Name]                                    Anthony Bellantuoni

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                                                                   Exhibit 10.51

                                PLEDGE AGREEMENT

      This is a pledge agreement made as of October 8, 2000 between Scott Silk,
an individual residing at 30 Partridge Lane, Boxford, MA 01921, ("Pledgor") and
ePresence Inc., a Massachusetts corporation, with its principal place of
business located at 120 Flanders Road, Westboro, Massachusetts, 01581
("Pledgee").

                                   WITNESSETH:

      WHEREAS, the Pledgor has issued a secured promissory note (the "Note") of
even date herewith in the original principal amount of Twenty-Seven Thousand One
Hundred Ten Dollars and Forty Cents ($27,110.40) payable to the Pledgee pursuant
to its terms; and

      WHEREAS, as collateral security for the obligations of the Pledgor under
the Note, the Pledgor has agreed to pledge and grant to the Pledgee a first
priority security interest in 15,000 shares (the "Shares") of common stock of
the Pledgee that have been issued under an Executive Officer Restricted Stock
Agreement (the "Restricted Stock Agreement") between the Pledgor and the Pledgee
dated October 8, 1999, as more fully set forth herein;

      NOW THEREFORE, the parties hereto agree and acknowledge that the foregoing
recitals are true and correct and to the following:

      1. Pledge of Collateral. As collateral security for the performance of the
obligations of the Pledgor under the Note (the "Obligations"), the Pledgor
hereby pledges and grants to the Pledgee a security interest in and to the
Shares held by the Pledgor, and any and all stock rights, powers and other
distributions, dividends or proceeds thereof. In addition, any stock rights,
dividends, powers or other distributions or proceeds received by the Pledgor
shall be held in trust for and delivered to the Pledgee to be held in accordance
with the terms of this Agreement, and shall be included in the Shares described
above.

      2. Delivery of the Shares. The Shares have been delivered to the Pledgee
on the date hereof, together with undated stock powers executed in blank. Upon
payment in full of the Notes, the Pledgee shall return to the Pledgor the
Shares, undated stock powers as well as such other instruments, documents, stock
certificates, money and goods as may come into Pledgee's possession from time to
time, whether through delivery by Pledgor or otherwise.

      3. Pledgee's Rights and Duties with Respect to the Collateral. Pledgee's
only duty with respect to the Shares shall be to exercise reasonable care to
secure the safe custody thereof all other duties being hereby expressly
disclaimed. Pledgee shall have the right, but not the obligation, to (a) demand,
sue for, receive and collect all money or money damages payable on account of
any Shares, (b) protect, preserve or assert any other rights of Pledgor or take
any other action with respect to the Shares, and (c) pay any taxes, liens,
assessments, insurance premiums or other charges pertaining to Shares. Any
expenses incurred by Pledgee under the preceding sentence shall be paid by
Pledgor upon demand and become part of the Obligations secured by the Shares.
Pledgee shall be relieved of all responsibility for the Shares upon surrendering
them to Pledgor.

      4. Pledgor's Warranties and Indemnity.
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            4.1 Pledgor represents, warrants and covenants (a) that Pledgor is
the lawful owner of the Shares, (b) that the Shares are fully paid and
nonassessable, (c) that as of the date hereof, the Shares are free and clear of
all liens, encumbrances, and security interests, other than the security
interest granted by the Pledgor hereunder, and this pledge constitutes a valid
and perfected security interest in the Shares enforceable against the Pledgor,
(d) that the Shares are not subject to any outstanding rights of redemption or
options to purchase or sell except as set forth in the Restricted Stock
Agreement, (e) that the Pledgor has the sole right and lawful authority to
pledge the Shares and otherwise to comply with the provisions hereof, (f) no
litigation is pending or threatened against the Pledgor, which if adversely
determined, would have a material adverse effect against the Pledgor or the
Pledgee's rights in respect of the Shares, (g) that the Pledgor agrees to defend
the Pledgee's title in the Shares and the security interest therein against any
and all claims and demands, and (h) this Agreement constitutes the legal, valid
and binding obligation of the Pledgor, enforceable against the Pledgor in
accordance with its terms.

            4.2 If any adverse claim is asserted in respect of the Shares or any
portion thereof, except as such may arise from the wanton, reckless or
unauthorized acts of the Pledgee, the Pledgor agrees to indemnify the Pledgee
and hold the Pledgee harmless from and against any reasonable liabilities or
damages, and reasonable attorney's fees incurred by the Pledgee in exercising
any right, power or remedy of the Pledgee hereunder.

      5. Voting of Collateral. While Pledgor is not in default hereunder,
Pledgor may vote the Shares, provided that said voting shall be in conformity
with the Pledgor's performance under this Agreement and the Note.

      6. Dividends and Other Distributions. While Pledgor is not in default
hereunder, Pledgor may receive all cash dividends, payments of principal and
interest, and other cash distributions payable with respect to Shares, provided,
however, that Pledgor shall immediately inform Pledgee of the receipt of any
such dividend, payment or other distribution and shall hold the amount thereof
in trust for Pledgee unless and until Pledgee shall in writing release Pledgor
from such trust. Pledgor shall cause all non-cash dividends and distributions
with respect to Shares to be distributed directly to Pledgee, to be held by
Pledgee as additional Shares, and if any such distribution is made to Pledgor he
shall receive such distribution in trust for Pledgee and shall immediately
transfer it to Pledgee.

      7. Pledgor's Default. Pledgor shall be in default hereunder upon the
occurrence of any of the following events ("Defaults"):

            (a) Any event of default shall occur under the Note;

            (b) If any lien, encumbrance or adverse claim of any nature
whatsoever is asserted with respect to any Shares (except pursuant to this
Pledge Agreement);

            (c) If any warranty of Pledgor hereunder is or shall become false;

            (d) If Pledgor fails to fulfill any obligation hereunder;

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            (e) If Pledgor fails to pay or perform any of the Obligations when
such payment of performance is due.

      8. Pledgee's Rights upon Default. Upon the occurrence of any default as
defined in Section 7 hereof, Pledgee may, if Pledgee so elects in its sole
discretion, take any one or more of the following:

            (a) at any time and from time to time sell, assign and deliver all
or any part of the Shares, or any interest therein, at any public or private
sale, for cash, on credit or for other property, for immediate or future
delivery without any assumption of credit risk, and for such price or prices and
on such terms as Pledgee in its absolute discretion may determine; provided that
(i) at least ten (10) days' notice of the time and place of any such sale shall
be given to Pledgor, and (ii) in the case of any private sale, such notice shall
also contain the terms of the proposed sale and Pledgee shall sell the Shares
proposed to be sold to any purchaser procured by Pledgor who is ready, willing
and able to purchase, and who prior to the time of such sale tenders the
purchase price of, such Shares on terms more favorable to Pledgee than the terms
contained in such notice; provided, further, the Pledgor acknowledges that the
Pledgee may be unable to effect a public sale of all or part of the Shares by
reason of certain prohibitions contained in the Securities Act of 1933, as
amended, and may be compelled to resort to one or more private sales to a
restricted group of purchasers who will be obligated to agree, among other
things, to acquire such securities for their own account, for investment, and
not with a view to the distribution or resale thereof. The Pledgor acknowledges
that any such private sale may be at prices and on terms less favorable to the
seller than if sold at public sales and that private sales shall be deemed to be
made in a commercially reasonable manner notwithstanding that such a private
sale may result in a lower sale price;

            (b) exercise the right to vote, the right to receive cash dividends
and other distributions, and all other rights with respect to the Shares as
though Pledgee were the absolute owner thereof, whether or not such rights were
retained by Pledgor as against Pledgee before default;

            (c) transfer the Shares into the name of the Pledgee and become sole
and absolute owner thereof;

            (d) exercise all other rights available to a secured party under the
Uniform Commercial Code or other applicable law or hereunder; and

            (e) the rights and remedies available pursuant to the Agreement are
cumulative, and not exclusive of any other rights or remedies otherwise
available to the Pledgee.

      9. Application of Sale Proceeds. In the event of a sale of Shares, the
proceeds shall first be applied to the payment of the expenses of the sale,
including brokers' commissions, counsel fees, any taxes or other charges imposed
by law upon the Shares or the transfer thereof and all other charges paid or
incurred by Pledgee pertaining to the sale; and, second, to satisfy outstanding
Obligations, in the order in which Pledgee elects in its sole discretion; and,
third, the surplus (if any) shall be paid to Pledgor.

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      10. Notices. All notices made or required to be made hereunder shall be
sent by United States first class or certified or registered mail, with postage
prepaid, or delivered by hand to Pledgee or to Pledgor at the addresses first
above written. Notice by mail shall be deemed to have been made on the date when
the notice is deposited in the mail.

      11. Heirs, Successors, Etc. This Agreement and all of its terms and
provisions shall benefit and bind the heirs, successors, assigns, transferees,
executors and administrators of each of the parties hereto.

      12. Pledgee's Forbearance. Any forbearance, failure or delay by Pledgee in
exercising any right, power or remedy hereunder shall not be deemed a waiver of
such right, power or remedy. Any single or partial exercise of any right, power
or remedy of Pledgee shall continue in full force and effect until such right,
power or remedy is specifically waived in writing by Pledgee.

      13. Further Assurances. The Pledgor covenants and agrees to execute and
deliver, or cause to be executed or delivered, all such other stock powers,
proxies, instruments, and documents, and will take such other action or actions
as the Pledgee may reasonably request from time to time in order to carry out
the provisions and purposes hereof.

      14. Termination. This Agreement and the pledge and security interest
represented hereby shall terminate upon the indefeasible payment in full of the
Note.

      15. Miscellaneous. (a) This Agreement or any part thereof cannot be
changed, waived, or amended except by an instrument in writing signed by
Pledgee; and waiver on one occasion shall not operate as a waiver on any other
occasion. (b) The Uniform Commercial Code and other laws of the Commonwealth of
Massachusetts shall govern the construction and enforcement of this Agreement.
(c) If any part of this Agreement or any agreement, document, or instrument
executed in connection herewith shall be deemed invalid or unenforceable by a
court of competent jurisdiction, the remaining provisions shall remain in full
force and effect, and shall continue to be binding upon the parties. (d) This
Agreement may be executed in one or more counterparts, each of which shall
constitute an original, but all of which, when taken together, shall constitute
one and the same instrument.

      16. Jurisdiction. The Pledgor irrevocably submits to the jurisdiction of
the courts of the Commonwealth of Massachusetts and the United States District
Court for the District of Massachusetts for the purpose of any suit, action or
other proceeding brought by the Lender arising out of or relating to this
Agreement, and the Pledgor waives and agrees not to assert by way of motion, as
a defense or otherwise in any such suit, action or proceeding, any claim that
the Pledgor is not personally subject to the jurisdiction of the courts of the
Commonwealth of Massachusetts or the United States District Court for the
District of Massachusetts or that the Pledgor's property is exempt or immune
from execution or attachment, either prior to judgment or in aid of execution,
that the suit, action or proceeding is brought in an inconvenient forum or that
the venue of the suit, action or proceeding is improper, or that this Pledge
Agreement or the subject matter hereof may not be enforced in or by such court.

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THE PLEDGOR HEREBY WAIVES ANY AND ALL RIGHTS TO A TRIAL BY JURY IN ANY ACTION OR
PROCEEDING IN CONNECTION WITH ALL MATTERS CONTEMPLATED HEREBY AND DOCUMENTS
EXECUTED IN CONNECTION HEREWITH.

      EXECUTED under seal as of the date first above written.

      PLEDGOR:

      /s/ Scott Silk
      --------------------------------
      Scott Silk

      PLEDGEE:

      ePresence Inc.

      /s/ Richard M. Spaulding
      --------------------------------
      By: Richard M. Spaulding
      Its: SVP & CFO

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