ATI Video card problem with XP Pro

[bullion416]

I have a 64mb DDR ATI Radeon. I am running win xp pro and when I am playing Quake III I am getting these random, out of place lines. They look like factures. But they only appear for a fraction of a second. What could be causing this problem? Is it some sort of software conflict with windows xp or could it be a hardware issue? Thanks