Sounds like the graphics driver has become corrupt. Assuming you`re on XP go to Control Panel>System and on the hardware tab select Device Manager. Expand the Display Adapter by the + sign and look for that display name. Right click and delete it. If it isn`t there look under monitor.
Reboot the computer and the system should re-install the driver. It may be worth checkin to see if you have the latest driver for your system from the manufacturers website but try this first.