I wish it was that simple... No, the CPU temperature barely exceeds 40°C, and I knew if it were overheating. Plus, it may hang after 20 minutes after bootup, or after 12 hours. It can happen while I'm doing various CPU intensive stuff or just idling. It's random. I didn't notice anything wrong with the power supply. Old computer never crashed and when I changed to the current one, I had two hangs the first evening. I don't think anything is conflicting, anyway, here's what System Information tool shows: So far I think it's none of the above, but thanks for the ideas. To tell that, I'd need to shut down and open the case. I'll probably look later, but it seems to work OK. Always, from the very first evening. Yes, I already said that. Did a clean install three times, one of them was with format. After one reinstall there were a few days when computer didn't hang at all. Then, after installing a codec pack (I think it was K-Lite) the system used to freeze after opening any movie. I uninstalled it and then installed Xvid separately. However, hangups returned. That's why I think there may be something to do with video codecs. Anyway, when I changed the computer, I installed the same video codecs that I had on the old computer, and they didn't cause any problems before. Furthermore, good hardware shouldn't hang because of Divx or Xvid installed, should it? There's one more thing. When I brought the computer to the warranty service, some jerk, after seeing win98, immediately decided to throw XP in, and he, being a jerk, mixed HDD's and installed XP on my HDD, destroying precious data. This was the time I had to reinstall after a format. Oh, and when I took back my computer, I've been told that it'd been working fluently for 2 days. So this may be an OS (bad support) problem. Well, I could just install XP and see what happens, but it would be a pain to reinstall everything, and after a few days, again reinstall everything (going back to 98). That's why I'm asking here if someone had similar experiences.