Fuzzy screen

When i leave a game running i sometimes get a bad display come up all a sudden. its similar to when a tv does when it hasn't got a signal. Its real fuzzy, when i exit the game,it no different at the desktop same little lines flickering.

I did a restart and it was fine, As it sorted itself out at restart im thinking its not the graphics card itself but something on windows xp?

 

If possible put another Monitor on system to rule that out.

-Del

 

Thanks for response.

I have tried another monitor also but still happens.

 

it's either interferance from something, or it's the graphics card.