In my experience XP 64 and 64 bit processors are not good friends. At my school they have AMD Athlon 64 boxes with XP 64, it takes ten minutes for them to start and once it gets to the desktop if it didn't crash while loading, everything lags even though they have a gig of RAM. I ask the admin if I could install Maya 7.0 PLE just for fun and I spent a lunch break trying to get the setup not to freeze.

Anyways, I checked Autodesk's website and no versions of Maya seems to support Vista. You could try moving to Linux, though you won't be able to play most gamess but at least your box won't crash every two minutes and no precious processing power will be wasted by the gui.