Windows XP restarting randomly (not overheat)

[Freeman14]

Computer specifications:

Operating System
MS Windows XP Professional 32-bit SP3
CPU
Intel Core 2 Duo E6750 @ 2.66GHz 44 °C
Conroe 65nm Technology
RAM
2.0GB Dual-Channel DDR2 @ 399MHz (5-5-5-18)
Motherboard
Intel Corporation DP35DP (J1PR)
Graphics
M208WA @ 1280x960
512MB GeForce 8800 GT (Undefined) 53 °C
ForceWare version 258.96
Hard Drives and Optical drives
ATAPI DVD A DH20A3H
JEL 5QN856V4 SCSI CdRom Device



Problem:

My computer keeps restarting for no apparent reason. I've performed a memtest, It passed. When I leave my computer on, doing nothing, it doesn't restart.

I've reinstalled my PC, formatting it completely, didn't help.

I've unchecked the "Automatically restart PC on error" and no BSOD shows up.

It's not overheating, since I've got a little monitor on my computer box, always monitoring the CPU heat, and it's always 40-50 degrees celsius.

Any idea what could be done?

 

[CCT]

If NOT using keyboard but just browsing, etc with mouse, does this happen?

Or the alternative (typing a bunch, no mouse).

 

[ComputerGuy55]

Yeah we need to narrow the problem down to something.. What hardware is plugged into your machine when this happens? (ex. Printers, cameras, mouse, keyboard, anything and everything) next, try running it with Only your mouse and keyboard.. if problem continues rule out extra hardware and focus on internal hardware(HD/RAM) and software..

After this, download a diagnosis program for your hard drive, the manufacturer of your hard drive will have one available free on their website, download, burn, and run. If no problems happen on the hard drive, it's probably fine.

When you run Memtest how many passes do you let it go ?

Since you say it does not restart if you leave it be, what are you doing on the computer at the time. Are you on the internet? Using a certain program?

If you are not on the internet, are you connected to the internet but just not using it at the moment?

Have you tried running in Safe Mode to see if the problem continues?

Check event viewer for any Warnings and Errors and post them here of what you find
Event viewer is located: Click Start Menu right click My Computer select Manage, on the left hand side, select Event Viewer Look in both the Application and System logs, the rest will not have any real useful information..

 

[Freeman14]

If NOT using keyboard but just browsing, etc with mouse, does this happen?

Or the alternative (typing a bunch, no mouse).

When I work with the mouse nothing happens, same for the keyboard.

It mostly happens when I am watching something on the net or playing video games.

 

[ComputerGuy55]

Seems like it may be a video or audio driver issue/hardware issue.

Try reinstalling drivers for your video card and test it..
Then try audio drivers, test it.. if you have onboard video test to see if it'll run without restarting with Onboard..

other things would be check the event viewer logs right after it restarts, see if anything shows up in there