<PAGE>

                                                                   EXHIBIT 4.2


NEITHER THIS WARRANT NOR THE SHARES ISSUABLE UPON EXERCISE HEREOF HAVE BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT")
OR ANY OTHER APPLICABLE SECURITIES LAWS IN RELIANCE UPON AN EXEMPTION FROM THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND SUCH OTHER SECURITIES LAWS.
NEITHER THIS WARRANT NOR THE SHARES ISSUABLE UPON EXERCISE HEREOF MAY BE SOLD,
PLEDGED, TRANSFERRED, ENCUMBERED OR OTHERWISE DISPOSED OF EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR IN A TRANSACTION
WHICH IS EXEMPT FROM REGISTRATION UNDER THE PROVISIONS OF THE SECURITIES ACT.

Great Neck, New York                                                 No.1

                             STOCK PURCHASE WARRANT

                  To Purchase 180,000 Shares of Common Stock of

                                 NAM Corporation

         THIS CERTIFIES that, for value received, ISO Investment Holdings, Inc.
(the "Holder"), is entitled, upon the terms and subject to the conditions
hereinafter set forth, at any time on or after May 10, 2000 (the "Initial
Exercise Date") and on or prior to the close of business on August 15, 2005 (the
"Termination Date") but not thereafter, to subscribe for and purchase from NAM
Corporation, a corporation incorporated in Delaware (the "Company"), up to one
hundred eighty thousand (180,000) shares (the "Warrant Shares") of Common Stock,
$.001 par value, of the Company (the "Common Stock"). The purchase price of one
share of Common Stock (the "Exercise Price") under this Warrant shall be $8.09.
The Exercise Price and the number of shares for which the Warrant is exercisable
shall be subject to adjustment as provided herein. In the event of any conflict
between the terms of this Warrant and the Stock Purchase Agreement, dated as of
May 10, 2000 (the "Purchase Agreement"), the Purchase Agreement shall control.
Capitalized terms used and not otherwise defined herein shall have the meanings
set forth for such terms in the Purchase Agreement.

         1. Title to Warrant. Prior to the Termination Date and subject to
compliance with applicable laws and the terms of this Warrant, this Warrant and
all rights hereunder are transferable, in whole or in part, at the office or
agency of the Company by the Holder hereof in person or by duly authorized
attorney, upon surrender of this Warrant together with the Assignment Form
annexed hereto properly endorsed.

         2. Authorization of Shares. The Company covenants that all shares of
Common Stock which may be issued upon the exercise of rights represented by this
Warrant will, upon exercise of the rights represented by this Warrant, be duly
authorized, validly issued, fully paid and nonassessable and free from all
taxes, liens and charges in respect of the issue thereof (other than taxes in
respect of any transfer occurring contemporaneously with such issue).
<PAGE>

         3. Exercise of Warrant. Except as provided in Section 4 herein,
exercise of the purchase rights represented by this Warrant may be made at any
time or times on or after the Initial Exercise Date, and before the close of
business on the Termination Date by the surrender of this Warrant and the Notice
of Exercise Form annexed hereto duly executed, at the office of the Company (or
such other office or agency of the Company as it may designate by notice in
writing to the registered Holder hereof at the address of such holder appearing
on the books of the Company) and upon payment of the Exercise Price of the
shares thereby purchased by wire transfer or cashier's check drawn on a United
States bank, the holder of this Warrant shall be entitled to receive a
certificate for the number of shares of Common Stock so purchased. Certificates
for shares purchased hereunder shall be delivered to the Holder hereof within
five (5) Trading Days after the date on which this Warrant shall have been
exercised as aforesaid. This Warrant shall be deemed to have been exercised and
such certificate or certificates shall be deemed to have been issued, and Holder
or any other person so designated to be named therein shall be deemed to have
become a holder of record of such shares for all purposes, as of the date the
Holder faxes a Notice of Exercise to the Company, provided that such fax notice
is followed by delivery of the original notice and payment to the Company of the
Exercise Price and all taxes required to be paid by Holder, if any, pursuant to
Section 5 prior to the issuance of such shares, have been paid within three (3)
Trading Days of such fax notice. If this Warrant shall have been exercised in
part, the Company shall, at the time of delivery of the certificate or
certificates representing Warrant Shares, deliver to Holder a new Warrant
evidencing the rights of Holder to purchase the unpurchased shares of Common
Stock called for by this Warrant, which new Warrant shall in all other respects
be identical with this Warrant.

         4. No Fractional Shares or Scrip. No fractional shares or scrip
representing fractional shares shall be issued upon the exercise of this
Warrant. As to any fraction of a share which Holder would otherwise be entitled
to purchase upon such exercise, the Company shall pay a cash adjustment in
respect of such final fraction in an amount equal to the Exercise Price.

         5. Charges, Taxes and Expenses. Issuance of certificates for shares of
Common Stock upon the exercise of this Warrant shall be made without charge to
the Holder hereof for any issue or federal or state transfer tax or other
incidental expense in respect of the issuance of such certificate, all of which
taxes and expenses shall be paid by the Company, and such certificates shall be
issued in the name of the holder of this Warrant or in such name or names as may
be directed by the holder of this Warrant; provided, however, that in the event
certificates for shares of Common Stock are to be issued in a name other than
the name of the holder of this Warrant, this Warrant when surrendered for
exercise shall be accompanied by the Assignment Form attached hereto duly
executed by the Holder hereof; and the Company may require, as a condition
thereto, the payment of a sum sufficient to reimburse it for any transfer tax
incidental thereto.

         6. Closing of Books. The Company will not close its shareholder books
or records in any manner which prevents the timely exercise of this Warrant.

         7. Transfer, Division and Combination.

            (a) The Holder (and its transferees and assigns), by acceptance of
this Warrant, covenants and agrees that it is acquiring the Warrants evidenced
hereby, and, upon exercise hereof, the Warrant Shares, for its own account as an

                                       2
<PAGE>

investment and not with a view to distribution thereof. The Warrant Shares have
not been registered under the Securities Act or any state securities laws and no
transfer of any Warrant Shares shall be permitted unless the Company has
received notice of such transfer, at the address of its principal office set
forth in the Purchase Agreement, in the form of assignment attached hereto,
accompanied by an opinion of counsel reasonably satisfactory to the Company that
an exemption from registration of such Warrants or Warrant Shares under the
Securities Act is available for such transfer. Upon any exercise of the
Warrants, certificates representing the Warrant Shares shall bear a restrictive
legend substantially identical to that set forth on the face of this Warrant
certificate.

            (b) This Warrant may be divided or combined with other Warrants upon
presentation hereof at the aforesaid office of the Company, together with a
written notice specifying the names and denominations in which new Warrants are
to be issued, signed by Holder or its agent or attorney. Subject to compliance
with Section 7(a), as to any transfer which may be involved in such division or
combination, the Company shall execute and deliver a new Warrant or Warrants in
exchange for the Warrant or Warrants to be divided or combined in accordance
with such notice.

            (c) The Company shall prepare, issue and deliver at its own expense
(other than transfer taxes) the new Warrant or Warrants under this Section 7.

            (d) The Company agrees to maintain, at its aforesaid office, books
for the registration and the registration of transfer of the Warrants.

         8. No Rights as Shareholder until Exercise. This Warrant does not
entitle the Holder hereof to any voting rights or other rights as a shareholder
of the Company prior to the exercise hereof. Upon the surrender of this Warrant
and the payment of the aggregate Exercise Price, the Warrant Shares so purchased
shall be and be deemed to be issued to such holder as the record owner of such
shares as of the close of business on the later of the date of such surrender or
payment.

         9. Loss, Theft, Destruction or Mutilation of Warrant. The Company
covenants that upon receipt by the Company of evidence reasonably satisfactory
to it of the loss, theft, destruction or mutilation of this Warrant certificate
or any stock certificate relating to the Warrant Shares, and in case of loss,
theft or destruction, of indemnity or security reasonably satisfactory to it
(which shall not exceed that customarily charged by the Company's transfer
agent) and upon surrender and cancellation of such Warrant or stock certificate,
if mutilated, the Company will make and deliver a new Warrant or stock
certificate of like tenor and dated as of such cancellation, in lieu of such
Warrant or stock certificate.

        10. Saturdays, Sundays, Holidays, etc. If the last or appointed day for
the taking of any action or the expiration of any right required or granted
herein shall be a Saturday, Sunday or a legal holiday, then such action may be
taken or such right may be exercised on the next succeeding day not a Saturday,
Sunday or legal holiday.

                                       3
<PAGE>

        11. Adjustments of Exercise Price and Number of Warrant Shares.

            (a) Stock Splits, etc. The number and kind of securities purchasable
upon the exercise of this Warrant and the Exercise Price shall be subject to
adjustment from time to time upon the happening of any of the following. In case
the Company shall (i) pay a dividend in shares of Common Stock or make a
distribution in shares of Common Stock to holders of its outstanding Common
Stock, (ii) subdivide its outstanding shares of Common Stock into a greater
number of shares of Common Stock, (iii) combine its outstanding shares of Common
Stock into a smaller number of shares of Common Stock or (iv) issue any shares
of its capital stock in a reclassification of the Common Stock, then the number
of Warrant Shares purchasable upon exercise of this Warrant immediately prior
thereto shall be adjusted so that the holder of this Warrant shall be entitled
to receive the kind and number of Warrant Shares or other securities of the
Company which he would have owned or been entitled to receive had such Warrant
been exercised in advance thereof. Upon each such adjustment of the kind and
number of Warrant Shares or other securities of the Company which are
purchasable hereunder, the holder of this Warrant shall thereafter be entitled
to purchase the number of Warrant Shares or other securities resulting from such
adjustment at an Exercise Price per Warrant Share or other security obtained by
multiplying the Exercise Price in effect immediately prior to such adjustment by
the number of Warrant Shares purchasable pursuant hereto immediately prior to
such adjustment and dividing by the number of Warrant Shares or other securities
of the Company resulting from such adjustment. An adjustment made pursuant to
this paragraph shall become effective immediately after the effective date of
such event retroactive to the record date, if any, for such event.

            (b) Dilutive Issuances. In the event that the Company shall sell or
issue at any time after the date of issuance of this Warrant and prior to its
termination, shares of Common Stock, or securities of the Company convertible
into or exchangeable for shares of Common Stock, at a price per share or
conversion or exercise price per share which is: (x) less than the Exercise
Price and the Exercise Price is less than the Market Price, as defined below, at
the time of issuance; or (y) less than the Market Price and the Market Price is
less than the Exercise Price at the time of issuance (each, a "Dilutive
Issuance"); then the Exercise Price shall be adjusted to a new Exercise Price
(calculated to the nearest cent) determined by dividing:

            (i) an amount equal to (A) the total number of shares of Common
                Stock outstanding on the date of issuance of this Warrant
                (determined on a fully-diluted basis; i.e., treating as
                outstanding all shares of Common Stock issuable upon exercise,
                exchange or conversion of all outstanding options, warrants, or
                other securities exercisable or exchangeable for or convertible
                into, directly or indirectly, shares of Common Stock) multiplied
                by the Exercise Price in effect on the date of issuance of this
                Warrant (subject, however, to adjustment in the manner set forth
                in this Section 11), plus (B) the aggregate of the amount of all
                consideration, if any, received by the Company for the Dilutive
                Issuance, by

                                       4
<PAGE>

           (ii) the total number of shares of Common Stock outstanding
                immediately after such Dilutive Issuance (determined on a
                fully-diluted basis as aforesaid).

In no event shall any such adjustment be made pursuant to this Section 11(b) if
it would increase the Exercise Price in effect immediately prior to such
adjustment.

In the case of the issuance of (x) options, warrants or other rights to purchase
or acquire Common Stock (whether or not at the time exercisable), (y) securities
by their terms convertible into or exchangeable for Common Stock (whether or not
at the time so convertible or exchangeable), or (z) options, warrants or rights
to purchase such convertible or exchangeable securities (whether or not at the
time exercisable):

                (1) the shares of Common Stock deliverable upon exercise of such
options, warrants or other rights to purchase or acquire Common Stock shall be
deemed to have been issued for a consideration equal to the consideration
(determined in the manner provided in subclauses (A) and (B) above), if any,
received by the Corporation upon the issuance of such options, warrants or
rights plus the minimum purchase price provided in such options, warrants or
rights for the shares of Common Stock covered thereby;

                (2) if the Exercise Price shall have been adjusted upon the
issuance of any such options, warrants, rights or convertible or exchangeable
securities, no further adjustment of the Exercise Price shall be made for the
actual issuances of Common Stock upon the exercise, conversion or exchange
thereof; and

                (3) on the expiration or termination of any such options,
warrants or other rights, the Exercise Price shall forthwith be readjusted to
such Exercise Price as would have been obtained had the adjustment made upon the
issuance of such options, warrants or other rights had not been made.

"Market Price" shall mean the average of the closing price of a share of Common
Stock as reported by the Nasdaq SmallCap Market for the five (5) trading days
preceding the date of issuance of a Dilutive Issuance.

         In the case of a Dilutive Issuance involving consideration other than
cash, the value of the non-cash consideration shall be that determined in good
faith by the Board of Directors.

         Upon each adjustment of the Exercise Price pursuant to this Section
11(b), the holder of this Warrant shall thereafter be entitled to purchase, at
the Exercise Price resulting from such adjustment, the number of Warrant Shares
obtained by multiplying the Exercise Price in effect immediately prior to such
adjustment by the number of Warrant Shares purchasable pursuant hereto
immediately prior to such adjustment, and dividing the product thereof by the
Exercise Price resulting from such adjustment.

         In no event shall the following issuances trigger the dilution
provisions of this Section 11(b): (i) the issuance or sale of options to
purchase securities, and the issuance of the securities underlying such options,

                                       5
<PAGE>

to employees, consultants and directors of the Company, pursuant to a stock
option plan approved by the Board of Directors of the Company; (ii) the issuance
of securities or options, and the issuance of the securities underlying such
options, pursuant to employment agreements approved by the Board of Directors;
(iii) securities issued pursuant to a public offering of the Company's
securities by means of a registration statement which is declared effective by
the Securities and Exchange Commission or securities issued thereafter; (iv)
securities issued in connection with a material acquisition which has been
approved by the Board of Directors of the Company; (v) securities issued in
connection with any stock split, stock dividend, or recapitalization of the
Company; (vi) Common Stock issued upon conversion of any shares of preferred
stock of the Company issued and outstanding as of the date hereof; (vii) shares
of Common Stock that may be issued pursuant to the Equity Line of Credit
available to the Company as of the date hereof; or (viii) the issuance of
securities which have, pursuant to the provisions of this Section 11(b), already
triggered or been exempted from triggering a reduction in the conversion price.

            (c) Reorganization, Reclassification, Merger, Consolidation or
Disposition of Assets. In case the Company shall reorganize its capital,
reclassify its capital stock, consolidate or merge with or into another
corporation (where the Company is not the surviving corporation or where there
is a change in or distribution with respect to the Common Stock of the Company),
or sell, transfer or otherwise dispose of all or substantially all its property,
assets or business to another corporation and, pursuant to the terms of such
reorganization, reclassification, merger, consolidation or disposition of
assets, shares of common stock of the successor or acquiring corporation, or any
cash, shares of stock or other securities or property of any nature whatsoever
(including warrants or other subscription or purchase rights) in addition to or
in lieu of common stock of the successor or acquiring corporation ("Other
Property"), are to be received by or distributed to the holders of Common Stock
of the Company, then Holder shall have the right thereafter to receive, upon
exercise of this Warrant, the number of shares of common stock of the successor
or acquiring corporation or of the Company, if it is the surviving corporation,
and Other Property receivable upon or as a result of such reorganization,
reclassification, merger, consolidation or disposition of assets by a holder of
the number of shares of Common Stock for which this Warrant is exercisable
immediately prior to such event. In case of any such reorganization,
reclassification, merger, consolidation or disposition of assets, the successor
or acquiring corporation (if other than the Company) shall expressly assume the
due and punctual observance and performance of each and every covenant and
condition of this Warrant to be performed and observed by the Company and all
the obligations and liabilities hereunder, subject to such modifications as may
be deemed appropriate (as determined in good faith by resolution of the Board of
Directors of the Company) in order to provide for adjustments of shares of
Common Stock for which this Warrant is exercisable which shall be as nearly
equivalent as practicable to the adjustments provided for in this Section 11.
For purposes of this Section 11, "common stock of the successor or acquiring
corporation" shall include stock of such corporation of any class which is not
preferred as to dividends or assets over any other class of stock of such
corporation and which is not subject to redemption and shall also include any
evidences of indebtedness, shares of stock or other securities which are
convertible into or exchangeable for any such stock, either immediately or upon
the arrival of a specified date or the happening of a specified event and any
warrants or other rights to subscribe for or purchase any such stock. The
foregoing provisions of this Section 11 shall similarly apply to successive
reorganizations, reclassifications, mergers, consolidations or disposition of
assets.

                                       6
<PAGE>

        12. Voluntary Adjustment by the Company. The Company may at any time
during the term of this Warrant, reduce the then current Exercise Price to any
amount and for any period of time deemed appropriate by the Board of Directors
of the Company.

        13. Notice of Adjustment. Whenever the number of Warrant Shares or
number or kind of securities or other property purchasable upon the exercise of
this Warrant or the Exercise Price is adjusted, as herein provided, the Company
shall promptly mail by registered or certified mail, return receipt requested,
to the holder of this Warrant notice of such adjustment or adjustments setting
forth the number of Warrant Shares (and other securities or property)
purchasable upon the exercise of this Warrant and the Exercise Price of such
Warrant Shares (and other securities or property) after such adjustment, setting
forth a brief statement of the facts requiring such adjustment and setting forth
the computation by which such adjustment was made. Such notice, in the absence
of manifest error, shall be conclusive evidence of the correctness of such
adjustment.

        14. Notice of Corporate Action. If at any time:

            (a) the Company shall take a record of the holders of its Common
Stock for the purpose of entitling them to receive a dividend or other
distribution, or any right to subscribe for or purchase any evidences of its
indebtedness, any shares of stock of any class or any other securities or
property, or to receive any other right, or

            (b) there shall be any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company or any
consolidation or merger of the Company with, or any sale, transfer or other
disposition of all or substantially all the property, assets or business of the
Company to, another corporation or,

            (c) there shall be a voluntary or involuntary dissolution,
liquidation or winding up of the Company;

then, in any one or more of such cases, the Company shall give to Holder (i) at
least 10 days' prior written notice of the record date for such dividend,
distribution or right or for determining rights to vote in respect of any such
reorganization, reclassification, merger, consolidation, sale, transfer,
disposition, liquidation or winding up, and (ii) in the case of any such
reorganization, reclassification, merger, consolidation, sale, transfer,
disposition, dissolution, liquidation or winding up, at least 10 days' prior
written notice of the date when the same shall take place. Such notice in
accordance with the foregoing clause also shall specify (i) the date on which
any such record is to be taken for the purpose of such dividend, distribution or
right, the date on which the holders of Common Stock shall be entitled to any
such dividend, distribution or right, and the amount and character thereof, and
(ii) the date on which any such reorganization, reclassification, merger,
consolidation, sale, transfer, disposition, dissolution, liquidation or winding
up is to take place and the time, if any such time is to be fixed, as of which
the holders of Common Stock shall be entitled to exchange their shares of Common
Stock for securities or other property deliverable upon such disposition,
dissolution, liquidation or winding up. Each such written notice shall be
sufficiently given if addressed to Holder at the last address of Holder
appearing on the books of the Company and delivered in accordance with Section
16(d).

                                       7
<PAGE>

        15. Authorized Shares. The Company covenants that during the period the
Warrant is outstanding, it will reserve from its authorized and unissued Common
Stock a sufficient number of shares to provide for the issuance of the Warrant
Shares upon the exercise of any purchase rights under this Warrant. The Company
further covenants that its issuance of this Warrant shall constitute full
authority to its officers who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for the Warrant
Shares upon the exercise of the purchase rights under this Warrant. The Company
will take all such reasonable action as may be necessary to assure that such
Warrant Shares may be issued as provided herein without violation of any
applicable law or regulation, or of any requirements of the principal market
upon which the Common Stock may be listed. Upon the request of Holder, the
Company will at any time during the period this Warrant is outstanding
acknowledge in writing, in form reasonably satisfactory to Holder, the
continuing validity of this Warrant and the obligations of the Company
hereunder.

        16. Miscellaneous.

            (a) Jurisdiction. This Warrant shall be binding upon any successors
or assigns of the Company. This Warrant shall constitute a contract under the
laws of Delaware without regard to its conflict of law, principles or rules, and
be subject to arbitration pursuant to the terms set forth in the Purchase
Agreement.

            (b) Restrictions. The Holder hereof acknowledges that the Warrant
Shares acquired upon the exercise of this Warrant, if not registered, will have
restrictions upon resale imposed by state and federal securities laws.

            (c) Notices. Any notice, request or other document required or
permitted to be given or delivered to the Holder hereof by the Company shall be
delivered in accordance with the notice provisions of the Purchase Agreement.

            (d) Successors and Assigns. Subject to applicable securities laws,
this Warrant and the rights and obligations evidenced hereby shall inure to the
benefit of and be binding upon the successors of the Company and the successors
and permitted assigns of Holder. The provisions of this Warrant are intended to
be for the benefit of all holders from time to time of this Warrant and shall be
enforceable by any such holder or holder of Warrant Shares.

            (e) Indemnification. The Company agrees to indemnify and hold
harmless Holder from and against any liabilities, obligations, losses, damages,
penalties, actions, judgments, suits, claims, costs, attorneys' fees, expenses
and disbursements of any kind which may be imposed upon, incurred by or asserted
against Holder in any manner relating to or arising out of any failure by the
Company to perform or observe in any material respect any of its covenants,
agreements, undertakings or obligations set forth in this Warrant; provided,
however, that the Company will not be liable hereunder to the extent that any
liabilities, obligations, losses, damages, penalties, actions, judgments, suits,
claims, costs, attorneys' fees, expenses or disbursements are found in a final
non-appealable judgment by a court to have resulted from Holder's negligence,
bad faith or willful misconduct.

                                       8
<PAGE>

            (f) Amendment. This Warrant may be modified or amended or the
provisions hereof waived with the written consent of the Company and the Holder.

            (g) Severability. Wherever possible, each provision of this Warrant
shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Warrant shall be prohibited by or
invalid under applicable law, such provision shall be ineffective to the extent
of such prohibition or invalidity, without invalidating the remainder of such
provisions or the remaining provisions of this Warrant.

            (h) Headings. The headings used in this Warrant are for the
convenience of reference only and shall not, for any purpose, be deemed a part
of this Warrant.

         IN WITNESS WHEREOF, the Company has caused this Warrant to be executed
by its officer thereunto duly authorized.


Dated:  May 10, 2000


                           NAM Corporation



                           By:
                              -------------------------------------------------
                              Roy Israel, President and Chief Executive Officer





























                                       9
<PAGE>

                               NOTICE OF EXERCISE



To:  NAM Corporation
     1010 Northern Boulevard, Suite 336
     Great Neck, New York 11021


(1)  The undersigned hereby elects to purchase ________ shares of Common Stock
     (the "Common Stock"), of NAM Corporation pursuant to the terms of the
     attached Warrant, and tenders herewith payment of the exercise price in
     full, together with all applicable transfer taxes, if any.

(2)  Please issue a certificate or certificates representing said shares of
     Common Stock in the name of the undersigned or in such other name as is
     specified below:


-------------------------------------------------
                (Name)

-------------------------------------------------
              (Address)




Dated:

------------------                        ------------------------------
                                                    Signature























                                       10
<PAGE>

                                 ASSIGNMENT FORM

(To assign the foregoing warrant, execute this form and supply required
information.
Do not use this form to exercise the warrant.)



        FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced
thereby are hereby assigned to___________________________________________ whose
address is___________________________________________________________________.

Dated: ______________, _______


Holder's Signature: _____________________________

Holder's Address:______________________________________________________________

Signature Guaranteed:  ___________________________________________

NOTE: The signature to this Assignment Form must correspond with the name as it
appears on the face of the Warrant, without alteration or enlargement or any
change whatsoever, and must be guaranteed by a bank or trust company. Officers
of corporations and those acting in an fiduciary or other representative
capacity should file proper evidence of authority to assign the foregoing
Warrant.
































                                       11