rogy

I bought myself a new computer recently and I am already having problems with the graphics card. My hardware: Intel Core2Duo E7400(2.8GHz), AsRock g31m-gs motherboard, and the Nvidia Geforce 9500 GT graphics card. I'm only having problems with graphicly more demanding games(i.e. CoD2 and the not so demanding Warcraft III, toribash works perfectly fine) when I enter the game for about 30secs everything works just fine, but then the game freezes for 3secs and the textures get all mixed up(see the screenshots). Than the textures get mixed up again every 30secs. The problem isn't overheating because the T of the card never gets past 60°C. The screenshots: Please help!