Crazy/Evil/Devil Problem

Ok...I recently formatted my computer. No big deal, I do it about every 6 months. The problem is with my video driver.

After I install my video driver, which I got directly from the nVidia site, I can play video games, and the graphics work fine, but when I attempt to play any sort of video or anything online (.mpg, .mp4, .avi, or anything off of YouTube) I locks up the computer, and screen starts to flash on and off, and, more often than not, it reboots my computer.

I attempted to uninstall my driver, and, oddly enough, when I do that, I can view any sort of video file or online video, but cannot play any sort of game.

This problem is very, VERY, annoying, since anytime I want to watch a movie I have to uninstall and reboot, then reinstall to play a game.

If anyone has any ideas about how to fix this, please respond.