90% of the time this is a driver problem. Does the error screen display a .dll file? I've been having problems on and off related to this and it's due to nv4_disp.dll. Try updating your drivers or even cleaning them and reinstalling if they're already current. Remember to uninstall the driver before you install the updated one, as registry codes will still be malingering, possibly leading to bad function calls, etc. etc.
Your PSU might also be underpowered, so make sure you're getting enough power on the 12V rail(s).
What fixed my problem was bad IRQ assignments through the BIOS. My BIOS was automatically assigning video card IRQs to already used IRQs -- by setting the BIOS to 'plug and play OS' (something I had forgotten to do) the problem went away, as Windows re-assigned the other IRQs, leaving the BIOS setting for the video card IRQ all by its lonesome in the IRQ space!