I've been running my nvidia 6600 for about 3 years now on my dell dimension 5150. Its a windows xp machine. yesterday, the computer suddenly restarted it's self. from that point on when ever it entered windows, it would lock up, freeze, or show some graphical error of the windows loading screen.
I reformatted, to my chagrin and reinstalled xp. It loads perfectly fine as long as i don't install any graphics drivers. I browsed a few forums offhandedly as i'm not computer suave. I tried the latest nvidia drivers, the oldest, dna-force, and omegadrivers. none of them seem to get me in to windows.
Let they all load safe mode fine.
so the card is acting up when the driver is installed? have you OC your card before? i have a friend who have trouble after OCing his card. every time he enter the windows the screen color are acting up. he try any driver possible but no luck. but the card is working fine as long as the drivers are not installed.
on the other hand maybe your card start showing its age.