game/program freezes but not OS

The problem that I am experiencing happens once ever 4-6 days where the program that I am using suddenly freezes and remains in the foreground while all the background programs such as winamp, emule and the OS still seems to be running. alt-tabbing, alt-f4 and ctrl-alt-del does not seem to work. So far it has only happened in warcraft III, Ys VI, Ys eternal and epsxe (psx emulation). The num-lock and caps-lock button still works so the OS hasn't frozen completly.

I was suspecting it would be the GPU but after using benchmark2001 se unregistered version for 8 hours I haven't gotten any problems with it. Does it mean my GPU is fine if it passes benchmark2001 if it ran okay for 8 hours? I selected all the tests btw. Should I try a different program for testing my GPU for errors? I don't know if my GPU is perfectly fine or not even though I ran it for 8 hours.

Do you think it is a hardware is an issue? How do you get out of a program that freezes and remains on the foreground that doesn't budge without pressing the restart button?


Heres my system specs:

Enlight 350W psu
Asus P5P800 SE mainboard socket 775 bios ver 0803
2x 512MB OCZ RAM
pentium 4 631 dual core 3.0GHZ
Geforce 6800 512MB forceware ver 78.01
Onboard soundmax soundcard
Linksys wireless-G PCI card
Quantum 200GB hd
Maxtor 40GB hd
1 generic floppy drive
creative DVD-R
using windows xp professional

Have you stress tested the entire system with Prime95 or similar for 24 hours?
I'm a little concerned that your PSU isn't feeding your system enough juice.