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For the last 2 years or so, my PC has been rebooting itself intermittently. There is no discernable pattern to the reboots, only that they seem most likely when I'm just about to press the "save" button.

It seems to come in waves. For instance, it was really bad about 8 months ago. The PC would reboot every 15 minutes. After a while it'd be good for six hours, then reboot again. Then it'd be fine for another week or so and out of the blue, boom. It started again Friday after many months of being fine, and has been problematic since then. Though I did have a 30 hour stretch Sunday where it was fine.

One more thing I've noticed, intentionally rebooting the machine or shutting it down for a while seems to increase the frequency of the problem. But overall it's rewally arbitrary. It makes it really difficult to determine the cause when there is no pattern to it. All I can do is swap out a part and wait for a reboot, and that'd prove that part wasn't the cause.

It's not a software problem as it happens in Windows and Linux. It's not a heat issue as temperatures are normal, and heat isn't in excess. It's happened when the PC is cool and hot, and everywhere inbetween.

I've also ruled out the PSU, GPU, ram, and HDD. Each of these have been removed or swapped out and the problem has still ocurred.

Really all that's left is the motherboard and CPU, but I don't have any spare parts to swap in to test it.

Possibly related, my BIOS is frequently reset. I have to go in and fix my clock, boot order, and other settings. This makes me think it's a motherboard issue, but I know very little about motherboards.

Does anybody have any insight into what the cause of this might be? I've been struggling with this issue for years, and it's causing problems with my work now and needs to be fixed.

System Specifications here

Motherboard specifications here

Thank you.

share|improve this question
how old is the system overall? The exact specifications would help as well. – Journeyman Geek Apr 19 '12 at 10:18
@Breakthrough: It happens in both Linux and Windows. – Daniel Andersson Apr 19 '12 at 10:32
I know you swapped out your RAM, but that's not a good way to ensure it's okay. Download Memtest86+, and ensure your RAM passes. To check your CPU, you can use Prime95 (just be careful, it causes very high CPU load, and thus high temperatures). – Breakthrough Apr 19 '12 at 10:41
Do u use an UPS or a Voltage Stabilizer? If yes, try changing them; if no, try using them. Helped me personally. – user129105 Apr 19 '12 at 10:58
See if there's any bulging caps. Its too new for that, but wouldn't hurt to check – Journeyman Geek Apr 19 '12 at 13:51

That you need to set the clock and boot order frequently means that the battery on the motherboard is bad. You could try to replace it.

Since you have ruled out other factors, perhaps the above manifests itself in reboots for some reason. Otherwise I'd suspect the PSU (always suspect the PSU :-) ). Or it is just a symptom of the motherboard being very old, which might have worn out other components as well. You say you have exchanged everything but the motherboard and CPU - it's probably one of those then. Probably the motherboard.

A distant last option is that your electricity is so spiky that the computer reboots, but you should notice this well more in lamps and other equipment. Computers are often less sensitive to this than other appliances since the PSU contains large capacitors to handle the power switching, and thus can handle short outages without problems.

share|improve this answer
I've already replaced the CMOS battery twice in the last year, that can't be it. I've also tried using two different PSUs, so I don't think that's the problem. As for voltage spikes, this has happened at three different homes if that indicates anything. I think it must be the motherboard. I appreciate your help. – SquareWheel Apr 19 '12 at 12:53
I suspect a heat issue. I cannotthink of any other issue besides a power supply problem that would cause a systme reboot besides the cpu causing it. – Ramhound Apr 19 '12 at 15:25
I've monitored the temperatures pretty closely and they're well within reason. It actually seems to happen more frequently when everything is cold, and begins rebooting less frequently after it gets going. – SquareWheel Apr 19 '12 at 17:14

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