I woke up this morning and started Half life 2 and when I got to the menu the computer froze. It happened everytime i got into the menu so I tried Doom3 and I got the same problem when i got to the menu. It doesnt happen on movies or anything, just games. I tried an older game like Counter strike and everything played just fine. One time when i rebooted windows told me the drivers had a drawing error so i reinstalled the nvidia drivers and i still have the problem. I tried changing it to 4x and AGP FW off and on but the same problem occurs. Here are my specs.

Windows XP SP2
ABIT Siluro FX 5600 256 mb
Asus K8N-E Deluxe Mobo
AMD Athlon64 3200+
1 gig of kingston ram
Soundblaster Audigy 2 ZS Gamer

Every part is brand new except for my vid card which was left over from my old system that was fried when the power supply blew. My computer has been working fine the past couple weeks untill this morning. Oh and all the fans work.
Oh, it was a left over part from a fried PSU. I'm going to say your card was damaged when the PSU fried. When a PSU goes it can take out your entire system. When you really stress out the card it goes belly up. That's a good indication of an over heating problem. There is probably a resistor or cap that took a surge, when the card heats up under stress, bada bing you have a problem.

I'd pick up a 5700, fairly cheap at, to tide you over for now. Or if you have the bucks, a 6600GT is a good bang for the buck right now.
yeah im deffinently going for the 6 series , even though its kinda over kill, but i couldnt figure out which one. My 5600 is 256 mbs, would traking a 6600GT @ 128 mbs be a speed cut?
no! the memory is just how much it can hold texture wise at a time, it all depends how fast the memory is, if u had 256mb of slow memory on a card and 128mb of fast memory on another card (the 6600GT)! then it would whoop its ass.

Anyway get a 6800GT the other parts of your system are high spec it would be well suited