Yeah I'd say it has to be the video driver. Vista is still pretty buggy for 3D stuff from what I hear/read. I, as a rule, never beta test operating systems because I don't have time to futz with little stuff like that.
Sounds like you need to setup multiple partitions and run XP or another OS along with Vista until Vista is more stable driver wise.
Of course this is just advice and doesn't really help your situation any.
Good luck though.
-BFC