I have been stumped with this one for a while and wanted to see if someone out there has an idea on what is causing my issue.
1) Computer has been off for 12hrs or more.
2) I boot it up (either from standby mode, or cold boot)
3) Computer locks up after about 5 minutes. It does not matter if I am gaming or surfing the web. Mouse stops moving and freezes up.
4) Hold down power button to reboot.
5) Computer runs great for hours without any problems.
My first thought was that something(temperature sensor) was not resetting until the forced shutdown in step 4. My next thought was that my PSU was bad and this might be the first place to start.
I have tried updating BIOS and drivers but this didn't solve anything. Reinstall XP does not work.
After doing step 4 in your process, download and install:
Open CPU-Z first, then HWMonitor. Monitor the readings in HWMonitor for about 10 minutes. If there are not drastic spikes in temps, run Prime95 on "blend". This will put 100% load on your CPU, and as a result, the CPU core temps will rise significantly. Monitor your temps again in HWM. Allow P95 to run for about an hour, that should be enough time. If your comp doesn't freeze, you can rule out CPU and CPU heat.
To test your GPU in the fashion you did with your CPU, run FurMark. Run this test for about 30 minutes or so. Again, if your comp doesn't freeze, then the GPU is likely safe and not causing your problem.
Next, download MemTest86 and burn the disc image to cd. Run the test on your RAM individually, that is one stick at a time. If you test all your sticks and find errors, you'd have to test them again individually anyway to determine which is bad. I suggest running this test last, as it will take the longest. Allow MT86+ to run for about 8 passes (this will take several hours).