Help me please, Radeon 9800 prob's!

Hello, Can someone help? I just built a computer with parts from Tiger Direct. Everytime I play a videogame, (mainly counter strike: source). It will shut down the whole computer after about 5 - 15 minutes, or do the VPU error on my graphics card. It is an ATI radeon 9800 pro 128 mb. I have tried updating my motherboard and processor drivers, turning off VPU, turning off Fast write on both Bios and the catalyst controller. I downloaded new drivers, rolled back the drivers? I also tried underclocking with the ATI tools. I cant think of anything else that I could do. Please help me out, I would really appreciate some ideas.

Here are my specs:

Ultra Wizard Black Mid Tower ATX Case
Maxtor 4G160J8 150 Gig Hard Drive
NEC ND-3550A 16x DVD Burner
Biostar K8t80 - A7 Socket 754 Motherboard
AMD Athlon 64 3300+ Socket 754 CPU (2.4 MHZ i think?)
Ultra 512MB PC3200 DDR 400MHZ CL3
Okia 450W Power Supply
Masscool AMD K8 Cooler Fan
ATI Radeon 9800 Pro 128 MB
Creative Labs zs Platinum Sound card w/ front control panel / controller

 

I would check the voltage of your PSU. Sounds like you do not have quite enough power for the card. I had a simular problem with random crashes, and finally checked the voltage on the PSU and it was low. A 'bigger' PSU solved the problem for me.

Also make sure you have adequate cooling on the video card itself. I put an aftermarket cooler on my 9800.

Good luck!

E