All my 3d games freeze

I upgraded my Motherboard, Ram, CPU. When I run a game, it will run completly smoothly. However, it always freeze in the middle of the game. It might take 5mins then 30mins. I even played for 1h long before freezing on time. I tried running in Graphics minimum, it froze after 5mins. When I say freeze, I mean.. image freeze, no sound, no hd. I have to completly reset everytime. Here's my spec:

A8V Deluxe -new
AMD 64bit 3500+ -new
2x 512mb DRR400 -new
Radeon 9600 Pro (had it on my old build)
Realtek enhance integrated audio -new
300Watt Power supply
I run WinXP SP2

At first, I thought my drivers would be the problem. I have the last Catalyst driver. I downloaded the last VIA chipset driver and the last realtek driver. I updated them but.. still don't work. After that, I thought it could be some kind of Graphic card config error. So I went on ATI Website and putted the optimal bios settings they were saying. (Pnp OS, AGP voltage 1.6v, 128mo aperture size...) I also tried reducing AGP speed to 4x with no fastwrite and combinating write and all. But still didn'T work. I tried changing the VIA driver for microsoft AGP drivers.. but didn't work. I then thought it might be due to overheating. After a reset I checked in the bios for my temperature probe. CPU 36 celcius (93 farenheit), Motherboard 26 (79 farenheit) celcius. That's quite good. I then thought it might be my integrated sound card. So I desactivated it and putted my Sound Blaster live 5.1 in it. Updated it with last driver but still froze. Grrr.. Then someone told me it might be my 300W power supply with my 4 fans that was doing that. So I bought a new 400W one. But still freeze. I've done 2 memory test. Memtest 96 and a Prime something. Everything is fine. I clean it of spyware and defrag and all but I just formated it when I built it. I've also opened the case and putted my room fan in it.. but.. it still froze. I'm lost. Please! Help me. I hope I don't have to change my Video card. I might try to put a second powersupply for the fans. And put a 8mm fan just for my videocard. But I don't think it's the problem. If anyone have a suggestion please help me!

 

450W minimum for that build.

 

I'll try putting all my fans on my old power supply.. and keep my 400W one for my HD, DVD and Mobo....

 

Why? Fans do about 4-5watt a piece, they're not the ones adding load.

 

well.. I'll test it out... I've put my 4 fans on an old mechanic power supply.. and everything else is on my 400W.. It'll maybe be ok since it didn't crash a lot... I'll go test it out.

 

Oh well.. it froze again. Ok now I'll try formatting someone told me it could help maybe there was something with my last install.. Wish me luck

 

,,,huh?

 

they dont look like they would fit hahaha what you do that with ms paint?

 

ok..! I haven't formatted yet but I got a new breakthrought.. It crashed during an installation! That's pretty good! That mean it's not my video card fault or anything! I'm sooooo happy. I'll try formatting now.