Hiya,
This is usually a sign of problems with a graphics card or its drivers. There's a chance that you may be using onboard graphics instead of a separate card as well, but if you're unsure if that's the case or if you simply need to update your drivers, post your system specs for us. You can find your card type by typing "dxdiag" into your Run command and looking at the Display tab. Another way is to right-click anywhere on your desktop, go to Properties, then the Settings tab, and look under "Display." It should say "somethingsomething on [ card ]." If you already know what kind of graphics card you have within your case, try going to the manufacturer's website and downloading the latest driver version.
