Per a conversation on TS today I thought I would post on how to install video drivers.  If you install video drivers over the existing drivers you may end up with corrupted video.  Sometimes not.

Download your drivers from Nvidia or ATI  to where you normally download to.  I use the desktop.

Go to control panel, then, add remove programs (XP) or Program and Features (Vista Win7)
Look for Nvidia drivers. (Sorry this is the only one I know of, ATI people chime in) Double click that and then select Remove only the following. Then check display driver only. After the display driver is uninstalled you will be asked to reboot.
Reboot into safe mode. Usually F8. Run driver sweeper for your display driver only. This will remove any remaining driver files.
http://downloads.guru3d.com/Guru3D---Driver-Sweeper-(Setup)-download-1655.html
Reboot into windows and install your display drivers as usual. You will be asked to reboot so do so into normal Windows. Now you can set up your desktop resolution.
After I install drivers I delete the Nvidia folder where it was extracted to. This would be your drive for your os. Usually C/

I recommend SLI users to reboot again after enabling SLI.

Hope this helps