I recently upgraded both my own PC and my girlfriend's PCs to Windows 7 64-bit. Both PCs were absolutely rock solid under XP and mine is still fine under 7. Hers, however, keeps crashing under 7 - but not XP (we've both dual-booted so we can test). Sometimes she'll get BSODs that relate to the graphics card, other times the game she's playing will crash back to the desktop without any error message at all, sometimes the whole PC just black screens.

I've reinstalled the latest graphics card drivers but I'm not convinced the problem is there as she and I both have the same graphics card. I've also disabled her Audigy 2 ZS and gone back to the onboard Realtek HD audio in case that was the problem.

If anyone's got any suggestions for troubleshooting I'd be grateful. Her system is:

Athlon 64 X2 5400+
Abit KN9S (BIOS 23, 15.51 nforce drivers)
4Gb DDR2-800 (4 x 1Gb)
GeForce GTX260-216
Sound Blaster Audigy 2 ZS (currently disabled)

Many thanks!