Instability

I bought a new computer and I've been having problems running Half-Life 2 and TF2 (the only 2 games I have so far). Everything runs great, but stability is an issue. Sometimes my computer will randomly crashes, the picture stays still and the sound goes into a EEEEEEEEEEEEEE loop and I have to reboot. What's going on? Sometimes I can play hours long without any problem just as it can crash again 10 minutes after restarting everything.

Asus P5Q3
Intel Core 2 Duo E8400 3ghz
2x2048MB Kingston DDR3 RAM
Ati Radeon Sapphire 1GB
Running Windows Home Edition 32-bit (in b4 enjoy your 3.25gb of RAM, I don't care unless it could be the problem)

seems like you havent deleted system32 yet.

>>2
Back to /b/, please.

check for latest drivers, run a memory test, and check your operating temperatures. Randomly timed problems are usually one of those 3 things.

don't forget the most common hardware problem that shits on everything : A shitty Power supply