set the two up w/o the adapter. Run a CAT-5/6 cable from any port of the router to the RJ-45 female connector on the motherboard of the "non-wireless" system. Then set up the Vista system to run off the wireless half of the router.

Computer ONE is hard-wired to the router and Computer TWO is set up wirelessly using on-board wireless adapter. Make sense??

and life goes on...