My rig started freezing on me a couple months ago and I don't know how to diagnose the cause. It only does it when I first start up the computer and let it idle at either the login screen (choose user and type password) or, having done that, at the desktop screen or on a browser. Again, if I don't let it idle and quickly load up a game and start playing, there is no issue. I play Warcraft 3 and if that is on the screen my computer has never frozen. It also seems that if/when I use the computer for a while and then go back to the desktop and let it idle, I do not have an issue, almost as if warming the computer up will keep it from stalling.
My rig specs are as follows:
ASUS p5K deluxe wifi mobo
3x1gb kingston ddr2 ram
Geforce 8800 GTS 640 mb
Intel Q6600 2.4ghz quad
I am running XP
(let me know if anything else is of interest to you)
We need to know the exact model of the PSU and RAM.
The first thing I would check is that the RAM is set to the proper specifications in BIOS. Check the manufacturer's website for the exact speeds, timings, and voltages the RAM should be using. Then manually set those specs in BIOS. After that, go to memtest.org and download MemTest86+. Burn the ISO file to a CD and set the computer to boot from the disc. Let this run overnight or through at least 7 passes. This will let you know if the RAM is good or not.