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                                                                   EXHIBIT 10.15



                                                                February 9, 1998



Michael Carabetta

Dear Mike,

I am pleased to confirm our offer to you for a position with Novadigm, Inc. (the
"Company") as President and Chief Operating Officer commencing on February 9,
1998. In this position you will be paid a semi-monthly salary equating to an
annualized amount of $200,000.

As a Company employee, you will also be eligible for an annual bonus of up to
$150,000 based on achieving quarterly targets, which we will mutually develop in
the next 30 to 60 days. In addition, you will also be eligible for benefits
which the Company makes generally available to its employees such as the
Company's 401 (k), and Employee Stock Purchase Plan.

As agreed, for the first two years of employment or until you elect otherwise,
you will provide your own medical and life insurance coverage. In addition, you
will accrue three weeks of vacation as well as all regular Company holidays.

In addition, you will be eligible to participate in the Company's Employee Stock
Option Plan. Under this plan, the Company will offer you incentive stock options
for the purchase of up to 400,000 shares ("Initial Grant"). The exercise price
of the option is determined by the commencement date of your employment. The
Initial Grant is otherwise subject to the terms and conditions of the Employee
Stock Option Plan and the standard form of agreement thereunder, including
vesting.

As President and Chief Operating Officer, you will report directly to me. Your
offices will be located 2200 Powell Street, Suite 590, Emeryville, CA.

If after 12 months, it is mutually agreed that relocation is appropriate, then
the Company will provide you will a relocation package, including reimbursement
for reasonable relocation expenses associated with the movement of your personal
and household goods, including transportation and en-route expenses, any third
party real estate fees associated with the sale of your house, temporary housing
as well as any federal and state taxes assessed for such move.

I have enclosed our standard "Employment, Confidential Information and Invention
Assignment Agreement." If you accept this offer, please sign and return


<PAGE>   2
Michael Carabetta
2/9/98
Page 2


the Agreement and this offer letter, to Vera Hunter in our Mahwah, NJ. You may
keep the enclosed copy of the offer letter for your files.

Employment information as well as various forms concerning taxes, insurance and
other benefits will be sent to you upon acceptance of this offer. These forms
must be completed and sent to Vera Hunter in order for you to begin employment.
If you would like your payroll directly deposited to your bank account, the
enclosed authorization agreement form must be filled out in its entirety and a
voided check must be attached for the account into which you would like the
funds deposited.

You should be aware that your employment with the Company is for no specified
period and constitutes at will employment. As a result, you are free to resign
at any time, for any reason or for no reason. Similarly, the Company is free to
conclude its employment relationship with you at any time, with or without
cause. However as a courtesy, both parties agree to provide each other 60 days
written notice.

In the event the Company terminates your employment without cause, you shall be
entitled to receive an amount equal to 25% of the bonus you would have earned
had you been employed by the Company at the end of such year for each completed
quarter in which your quarterly objectives were achieved. The bonus to which you
are entitled pursuant to this section shall be paid in a lump sum within thirty
(30) days of the date that the Company's releases its results to the public for
the quarter in which you were terminated.

In the event that your employment is terminated by the Company without cause
during the first three years of employment or you die during your employment
with the Company, you, or in the case of death your survivors, will be eligible
to purchase under the Company's Employee Stock Option Plan up to 100,000 shares
of your Initial Grant of 400,000 shares; plus up to 1/48th of the amount of your
Initial Grant for each completed month of employment.

If the Company terminates your employment as a result of Involuntary or
Constructive Termination other than for Cause at any time during the period
beginning thirty (30) days before and ending twelve (12) months after a Change
of Control, then you shall be entitled to receive, in addition to any other
benefits, 100% accelerated vesting of your stock options.

For the purpose of this employment offer, a Change in Control shall mean the
occurrence of any of the following: (i) any person becomes the beneficial owner,
directly or indirectly, of the securities of the Company representing 50% or
more of the voting power represented by the Company's then outstanding voting
securities; or (ii) a merger or consolidation of the Company with any other
corporation, other than a merger or consolidation which would result in the
voting securities of the Company outstanding immediately prior thereto
continuing to represent at least 50% of the total voting power of the surviving
entity



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Michael Carabetta
2/9/98
Page 3


immediately after such merger or consolidation.

For the purpose of this employment offer, Involuntary or Constructive
Termination shall mean (i) without your express written consent, the assignment
of any duties or the significant reduction of your duties, either of which is
inconsistent with your position with the Company and responsibilities in effect
immediately prior to such assignment, or your removal from such position and
responsibilities; (ii) without your express written consent, a substantial
reduction, without good business reasons, of the facilities and perquisites
available to you immediately prior to such reduction; (iii) a reduction by the
Company in your base compensation as in effect immediately prior to such
reduction; (iv) a material reduction by the Company in the kind or level of
employee benefits to which you are entitled immediately prior to such reduction
with the result that your overall benefits package is significantly reduced; (v)
without your express written consent, any relocation of your job or office more
than 40 miles from your then current job or office; (vi) any purported
termination of you by the Company which is not effected for Disability or for
Cause, or any purported termination for which the grounds relied upon are not
valid; or (vii) the failure of the Company to obtain the assumption of this
Agreement.

This letter and the enclosed agreement constitute the entire agreement between
you and the Company regarding your employment, and may be modified only in
writing. Terms of this offer are considered confidential information to the
Company and trust that you will treat it as such between you and the Company.

In accepting this offer, you are representing to us that (i) you are not a party
to any employment agreement or other contract or arrangement which prohibits
your full-time employment with the Company, (ii) you do not know of any conflict
which would restrict your employment with the Company, and (iii) you have not
and will not bring with you to your employment with the Company any documents,
records or other confidential information belonging to former employers. The
Company acknowledges the existence of a severance agreement that governs your
departure from The Amdahl Corporation.

In the event of any dispute or claim relating to or arising out of our
employment relationship, you and the Company agree that such disputes shall be
fully and finally resolved by binding arbitration conducted by the American
Arbitration Association in Alameda, County, California. However, we agree that
this arbitration provision shall not apply to any disputes or claims relating to
or arising out of the misuse or misappropriation of the Company's trade secrets
or proprietary information.



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Michael Carabetta
2/9/98
Page 4


Mike, we are very excited about having you as part of Novadigm and everyone is
eager to get you aboard and move forward with your added participation.



                                             Sincerely,


                                             /s/ ALBION FITZGERALD
                                             Albion Fitzgerald
                                             Chairman, President
                                             and Chief Executive Officer



Terms Agreed:




/s/ MICHAEL CARABETTA
-----------------------------------
Michael Carabetta





-----------------------------------
Date:



Enclosures

cc:     Compensation Committee of the Board of Directors