okay, so this is my first post, and Ive never OC'd anything, and most of my computer experience is self-taught... just a heads-up.
I got a brand new rig in Jan. '08
ASUS P5N- SLI
Intel Q6600 core 2 quad
2-ECS 8600 GT 256
3 GB of Kingston Value Ram @ 667Mhz
240 GB WD SATA drive
Since day one I've been having BSOD/freezes with nv4disp.dll has stopped responding as the error message. Sometimes runs great for days, sometimes crashes after ~15mins. Usually crashes during intensive graphics (ie: Oblivion at 1680x1050 max settings). I have updated BIOS, and tried every possible driver currently available for this card (using DCpro and safe mode, etc.). I am starting to suspect one of three possibilites as a cause-
Download the latest official drivers for both your motherboard and vid card. Then I'd grab Driver Cleaner Pro from guru3d clean all nVidia drivers out both mobo and vid card. Let us know how it goes and like Squeetard said it could be some other piece of hardware causing that problem so running the memtest86 (from windows imo as it stresses the ram more) is definately worthwhile.