99% of the adapters on the market place for USB to RS232 are meant to host additional COMM ports on a PC that has USB support. It just is not feasible to go the other way. At least I have not seem any reasonable products that provide USB connectivity to a computer that has COMM ports.

Since you say that your motherboard in your computer has full USB support there is a high degree of possibility that there is a connecter header on the motherboard that will permit you to bring USB to the outside of your computer case. Here are two links that show the kinds of products that are around to provide the capability you need.

http://www.frontx.com/cpx101_2.html

http://www.ebusinesscables.com/internal_...sb_hub.htm

MICHAEL KARAS