Random blue screen errors in Vista (dual boot w/XP)

Hey, all. I recently posted something about this problem relating to games; however, I've now observed it happening during general Vista use. Basically, it bluescreens at random, with equally indecipherable but subtly different error codes each time (different hex codes, whatever they may mean, at the bottom). It could be while running Supreme Commander on high settings, or it could be idle. CPU usage could be at 100% or hovering at around 0. That said, it is more likely to happen while the computer is under stress, but may occur at any time.

I'm running a dual-boot with XP, with an Athlon X2 4800 CPU (dual-core optimizer and everything else from the AMD site installed), 2 gigs of PC3200 RAM, a Radeon X1800XL video card, and twin 250-gig hard drives. I have not noticed any problem with this at all in XP. According to my performance monitors, idle and basic-use (OpenOffice, web browsing) CPU usage is about the same as on XP, and only slightly more RAM is used (27-29% for Vista vs. 22-24% in XP).

Anyone know anything that might help me with this problem? Thanks.

I'm getting the same behavior in my Vista 64 with Supreme Commander.
Running a QX6700 w/8gig RAM and an 8800GTX.
But since our hardware is different, it sounds like it is a software issue.
SupCom, Vista, or nVidia driver.
Are YOU using an nVidia video card?

Gigabyte DS3 rev 3.3
Hitachi 500GB drives
In Vista I turned off the sleep function.
Virus checker is "Avast!"