Was this a Vista Driver you rolled back to or was it a NVIDIA Win 7 driver?
Also are you running Win7 32bit or 64bit? I'm running 64bit.
Where can I find this driver as I have searched the net and can't find it.
I am experiencing the same problem Although it is not always the whole system, just the program I may be working in. Happens alot with when watching videos in Media Player and Media Center.