geforce fx 5900 crashing

I have a pny verto geforce fx 5900 card in a pc that i just built. I am new to building pcs(first one). My problem is that when I go to play games on this card it crashes after playing for only a few minutes and my comp restarts. Everything else works fine, just cant play games. I have 4 80mm case fans, 2 more on the power supply, the processor fan, the vid card fan, an expansion slot fan installed directly below the vid card, and another case fan located on the clear side directly above the vid card.I cant understand what the problem is. Pease help.

 

Take the card back while it's still under warranty and get them to test it or if you bought it online try it in another puter and see what happens