Hello! I have a question. The picture is glittering, like this:

(this is a GWX screenshot, but it's the same with stock versn)
I guess it's a graphic card settings problem (those filtrations etc, I'm not a pro in those), 'cause few days ago I had to reinstall the system; before that, everything was ok. Can you please share the suitable settings to solve it?
My configuration is
Intel Core 2 Quad Q6600
3Gb
2x GeForce 8800GTX SLI
XP SP2