My computer keeps rebooting.....if you have it turned off for a while *say 2 months* then it'll work....but then it will start rebooting...the more you use it the more often it reboots....
It's about to make me pull my hair out....I'm being forced to use someone elses computer for now...I need help!!!!!!!!!!!!!!!!

by the way, it's window xp and I've had someone reinstall the windows and such.......and after a while of rebooting more and more often then it won't even get the windows screen....

This can be caused by many things, including heat, failing RAM, failing motherboard, failing CPU, failing or overstressed power supply, or failing drive.

Make sure the system is clean of heat trapping dust, and that all fans spins freely. Inspect the motherboard for bulging or leaking electrolytic capacitors. These failed or failing capacitors are a common cause of sudden, but seemingly random system lock ups and reboots. The capacitors look like tall soda cans, many of which surround the CPU socket.

All older motherboards, and many of today's less expensive motherboards use electrolytic capacitors containing a liquid electrolyte. Failing (including flawed and/or abused/over-heated) capacitors literally bulge at the seams due to excessive internal pressures. Extreme (and very rare) cases result in a firecracker type explosion that can really stink up a room. Typically, electrolyte just oozes from the pressure relief points stamped in the tops of the capacitor casings (seen as a symbol or letter). The electrolyte can be caustic to motherboards and flesh. Look for white to dark-brown, dried liquid or foam on the tops or bottoms of the capacitors. Bulging capacitors are a sign leakage is about to occur.

A motherboard with bulging or leaky capacitors can be repaired, but often it is more cost effective in the long run to replace the motherboard.

Next time it boots into Windows, or if you can boot into Safe Mode, try disabling Automatic restart. This will cause the system to halt at the infamous blue screen of death (BSOD) instead of continually rebooting, and hopefully display a useful error code and message. And it will allow you to look for errors in the Event Log. To change the recovery settings to disable Automatic restart:

1. Right-click My Computer and go to Properties > Advanced

2. Under Startup and Recovery, click Settings to open the Startup and Recovery settings menu

3. Under System Failure, uncheck the Automatically restart check box, then click OK as needed to exit out

4. Restart the computer and see what happens

At this point, when/if a fatal error occurs, it should not automatically reboot, but give you the BSOD. This does not fix the problem causing the fatal errors, but it does stop the endless reboot cycle and hopefully allow further troubleshooting.