Try this: Put your system back the way it was intitially and then boot into the SAFE mode (F8). Do a System Restore, in safemode, for a time last week. Let me know what happens. I'm beginning to think you have a driver corruption issue and restore might help.
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.