Computer restarting

[Death BOO Z]

I have a quite new computer (P4, 2000 MHZ, win XP) but lately, it restarts randomly whenever it feels like it...
sometimes it happens even a minute after it restarted (before windowes is fully up) so i don't think it's a software problem, and also, if i keep the computer off for a few hours, it can work for a long time without restarting itself, but once it restarts, even if i try to work it again, it'll restart again in a few mintues...

does anybody have a clue for what might be causing this? overheating? power supplier? aliens?

[Kakafosha]

it sounds to me like an overheating issue. if possible check ALL your fans to see if they're correctly working. overclocking can also cause some overheating problems, so if you did make any changes i'd suggest you change them back. it might just need a better fan. i dont know much about fans but hopefully someone will reply with some answers. sometimes dust can cause some unwanted heating, but since you said its a fairly new computer that should be the issue. one thing i do, which a lot of other people do as well is take the side panel off your tower to help cool it out even more (not just for a while, i mean pretty much everytime you use your comp)

im pretty sure it isnt a trojan/virus issue, so you wont have to worry about that. i remember the fan on my power supply box died out and i pretty much had the same problem you had. letting it shut down for a while is obviously cooling it down so when you start it up again it'll last for a while. then it ends up heating up again and shutting down.

[Foomanchew24]

If you think it is a heat related issue you can download one of many programs that monitor the temperature and display it on the task bar. I use Motherboar Monitor 5, and have heard that Speed Fan is also a good program, that way you can see what temps your computer is at without having to go into your bios. Try one of those two and see what your temps get up to.

[devinen]

Actually, that sounds like a symptom of the blaster exploit. Just make sure that your computer is patched fully from windows update. Otherwise, it could be a number of things from an overheating processor to bad RAM. You can use a program like memtest to test out your memory.

[-ANBU-Sasuke-]

Check ur PSU, (powersource) and check the +12 volt rail, make sure ur computer isnt using more that it should be. To check how much ur computer is using, generaly it is in the BIOS, and i think Power management.

Check for virus and worms and ect.

Make sure there is no hardware interferance, (my friend had one thatt crashes in computer entirly when u boot up windows....)

[Jman]

if its not hardware related issue then it could be a virus of some some that runs at startup to set your pc to restart in an infinite loop.
what you can try is booting up in safe mode and see if the same thing happens or you can boot normally and hold the shift key while its loading to windows. this will prevent any tasks that start up on boot. from there you can check your startup tasks to monitor if any program is running that shouldn't be on there. i would also suggest you run checks for viruses spy/malware etc