If your running a multi GPU(GTX295 etc) Nvidia card and your system continuously crashes, try turning off the multi-gpu capabilities of it. I used to have this problem. Full blown system lock up with no hope of fixing it. My drivers would fail, no matter how old or new they were. In the Nvidia Control panel, under Multi-GPU, click the third option, "Disable Multiple GPU". Make sure the processor selection is at "Auto-Select" and save the actions. Then restart your computer and you should be brand new. If someone in Tech Support wants to re-write this, or put it in the Graphics part, feel free. Just thought I'd share.