This began to happen about a month ago. My computer would freeze regularly after I've been playing certain games for about half an hour to an hour (counter-strike 1.5 and 1.6, SimCity 4), but would never happen when I'm playing other games (Diablo 2 for example), or when I'm not playing games. I suspected this was because my video card was failing under intensive 3-D situations, so I replaced my GF2 MX 200 with a FX 5200, unfortunately that did not solve the problem at all. When my computer freezes, the screen will freeze, the sound will freeze (looping what was playing right before it froze over and over again), and my hard drive activity light would go off. My computer won't response to any keyboard/mouse input until I do a hard reset.
40G Maxtor HD
GF2 MX 200 64MB (before) / FX 5200 128MB (now), both using detonator 45.23 driver
Windows XP Pro + SP1 + all major patches and updates
This has become quite annoying to me, so any help/ideas would be greatly appreciated. I will check for responses frequently.