Start the computer in VGA mode pressing F8 right after the BIOS post... From the list of start options select VGA Mode and press Enter. Once in windows in VGA mode*, uninstall the video driver from the Device Manager. Start button > Right click Computer > select Manage > Device Manager > Display Adapters > Right click the Graphics Card > Properties > Driver tab > select Roolback driver. Next apply the 6 options I mentioned before.
*Just in case VGA mode doesn't help, select Safe Mode.