Computer Freeze-Up

So, I put this computer together, and it's running great. I can max out games and everything, without any slowdown. The only thing is, even when running small games, my whole system just locks up after a while, and I have to restart. Every time it does it, I reboot and run SpeedFan. It shows that my Core0 temp is coming down from 40C, but that shouldn't be enough to cause freezing. Also, I have a case fan, a CPU fan, and a GC fan, but SpeedFan is only showing two of them. That's kind of odd.

Lastly, I ran memtest86+, and that froze when it got to about 5 minutes. I had to restart, but it didn't show any problems.

What the fuck is going on?

If just running memtest made it freeze up (you rebooted into memtest off a CD right?) then It seems like one of your pieces of hardware is a bit faulty, maybe your ram (would choke the rest of the system). Everything you have is still in your return period so don't start worrying =o.

I'm afraid I dunno how to find out which part is to blame =(

I guess you could try taking out one of your sticks of ram and running off just a single 2GB stick for a while, see if it still does it. If it does, switch the 2GB stick with the other one you took out. If it doesn't after that, you know one of the sticks is bad.