Big Problem (system freezing)

[biohaZ]

I usually dont post on forums like these but with this im stumped. It all started when i was playing Team Fortress Classic (Half Life) and my computer completely froze up. I gotta hit the Tower button to restart it and then i tried again same thing happened. It does it at random times it could take 10 minutes, sometimes it could take 15 ect. At first i thought it was a virus so i ran a virus scan and it wouldnt even do that, it would freeze on the virus scan, after a while of doing it , it finially worked and i had no virus. So then i didnt feel like messing with it so i just reformated. After the reformat i went to go play, and noticed i still freeze. Then i opened up the case, to take a look, and noticed my ATI 9000 128Mb Fan wasnt working. I figured that was the problem so i just got lazy and ordered a 9600XT off the net. It was gonna take a few days to come in, so i just ran a huge window fan on my computer, opened up the case, and it kinda worked. It would freeze every 30 mins or so instead of 10. Then yesterday the video card came in, i hooked it up newest drivers ect. Went to play, and i freeze. Im at a loss here and cant think of anything. I checked the RAM with a ram test and the ram is fine. What do i do :(

[alc6379]

It could be a heat issue, especially if running a window fan on the system helped the issue.

First off, check the processor fan and the Power supply fan. Are both of those working? Also, what type of processor do you have? If those fans are working, feel to see how much heat is coming out of the back of your power supply. If it's pretty warm, you may have an issue there, and a replacement may be in order.

Could you post some specs on your system? Mainly, CPU, power supply wattage, and what type of motherboard. Maybe what CPU cooler you're using would help, too.

[biohaZ]

I have a 350ATX Power supply, all my fans are working, i have 2 case fans, my CPU fan is working good, my video card fan is working good. i got a CPUcool program that tells what temp ur running at and my CPU runs at about 30C. My motherboard is ECS Elitegroup P4S5A/DX+. I think the CPU fan is a intel fan, but im not sure. in the back of the power supply, its been kinda hot before, but right now its not to bad.