It's a common error.....my son used to get tons of them in WoW on his box (EVGA GTX295 FTW) ..... it also wouldn't maintain the factory OC...... 5 RMA's later they sent a 480 and that's been fine.
SOP is :
1. Uninstall Driver, reboot
2. Remove all things nVidia from BIOS w/ registry cleaner (Ccleaner), reboot
3. Install new driver, reboot
4. Run OCCT GPU test, observe temps and voltages for anything weird