No, it is generally not permissible to use art belonging to other people unless the art is released under a creative commons that allows for reproduction, republishing, copying, and distribution. If you can be more specific or show me the clip art and its source, I would be able to fully answer this question.
Without seeing your product license, and/or knowing exactly which clip art collection you refer to, I can only pass along the following from Microsoft's website (deep link provided):
"Clip Art and Sample Art
The End-User License Terms that accompany your software describe the permitted commercial uses of images, clip art, animations, sounds, music, shapes, video clips, and templates that accompanied the product. Find End-User License Terms for Microsoft products.
The Clip Art and Media gallery provides a compilation of artwork. See the use terms for the description of permitted uses. If those terms do not meet your needs, our Clip Art partners at Office Online provide a variety of images you can license directly.
In the absence of language to the contrary in the License Agreement, Sample Art (which includes images customarily found in the "sample" folders within Microsoft operating systems) may be used for personal use only. You may not sell, lease, or distribute Sample Art, or any materials you create that use Sample images, for any commercial purposes." - http://www.microsoft.com/en-us/legal/intellectualproperty/Permissions/default.aspx
Please let me know if I can be of further assistance, in this or in any other matter.
Terry L. Thomas
(650) 793 - 7129
THIS POST DOES NOT CONSTITUTE LEGAL ADVICE, DOES NOT IMPLY ANY ATTORNEY-CLIENT RELATIONSHIP, AND IS PROVIDED FOR GENERAL INFORMATIONAL PURPOSES ONLY.
Attorney Thomas' answer hjghlights the crucial detail here - the particular clip art you want to use is for _personal_ use only, and your intended use is _commercial_. That means either 1) get a license, 2) risk a copyright infringement lawsuit or 3) use some original or properly licensed art.
Avvo doesn't pay us for these responses, and I'm not your lawyer just because I answer this question or respond to any follow-up comments. If you want to hire me, please contact me. Otherwise, please don't expect a further response. We need an actual written agreement to form an attorney-client relationship. I'm only licensed in CA and you shouldn't rely on this answer, since each state has different laws, each situation is fact specific, and it's impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.