OT: Haunted Computer!

Jay Gladwell wrote on 6/28/2005, 3:07 PM

What would make a computer reboot itself? Sometimes I'm working, sometimes I'm not. I'm never doing the same thing twice when it just decides to reboot itself. I've tried going back to when it wasn't happening with "restore" and I've even reinstalled a mirrored backup of the C: drive--it still reboots itself, although not as often now!

Any ideas as to what's going on and how to resolve this problem?

Thanks!

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GlennChan wrote on 6/30/2005, 5:38 PM

Jay, the combination of prime95 and Motherboard Monitor (MBM) is a pretty methodical method for figuring out which part exactly is faulty. Are you able to run/install it?

Prime95

RAM: Faulty RAM would likely cause different BSODs, but I don't think it would cause your computer to reboot as long as you have windows set not to reboot on BSOD.
memtest86 is a pretty good RAM tester. In some cases, it will not catch heat-related failures (memtest will not cause your RAM to warm up, while rendering will) that happen every few hours.

Power supply: There are different ways to tackle this. Reducing the load on it is one way... video cards (from 10-80W), then hard drives (25W at boot, 15W while running) suck the most power of optional components. PCI cards typically use ~5W.

Another way is to manually measure voltages with a volt or multi-meter. Please ask for instructions.

MBM is an excellent way to get voltage readings. Hopefully it works with your motherboard.

CPU: Typically overheating will cause instability where your computer will randomly freeze or reboot or just shut down. Use a utility to get a CPU temperature reading... MBM, speedfan, or your motherboard manufacturer's utility
Prime95 will also catch CPU errors, and is needed to get more useful MBM readings.
Or you can try re-installing your CPU heatsink... there is a chance you can damage things while doing so. Read the appropriate manual (for the CPU).

Motherboard:
Leaky capacitors are one way motherboards can be flaky. If you run MBM, you should see voltages that are way out of spec. Or visually inspect the board and look for bulging capacitors, or brown crud on them.

Otherwise I really don't know of any good ways of figuring out whether or not your motherboard is bad. Swapping parts is one method- swap non-motherboard parts into another system, or swap another motherboard in.
Method of elimination is another way of figuring out if your motherboard is at fault.

Jay Gladwell wrote on 6/30/2005, 6:32 PM

Glenn, I can't run anything at this point for more than 20 or 30 minutes before it reboots. Thanks for your suggestions. I'm just going to start replacing things a piece at a time, starting with the least expensive items.

GlennChan wrote on 6/30/2005, 7:37 PM

Jay, in your case just try starting prime95 and loading up MBM right away and see what happens. It should take like 15 minutes.

You don't necessarily need to let things run overnight... that would just be for cases where you have flaky RAM that causes reboots/crashes every several hours or so.

Jay Gladwell wrote on 7/1/2005, 5:07 AM

Glenn, I'll give it a try and see what happens.

[edit]
It just keeps rebooting. I can't do anything, now!

GlennChan wrote on 7/1/2005, 11:30 AM

Jay, about how long does it take to reboot?
Does it reboot faster when you run prime95? (If so, it indicates an overheating problem. Check that the PSU fan is spinning by looking at it, or feeling for air coming out the back. Reinstall the CPU heatsink, but follow instructions or you can damage something. If the CPU heatsink uses thermal paste, you should remove it and apply some new paste such as Artic Silver per their instructions. If it's not that, check for leaking capacitors on your motherboard.)

What if you just run Motherboard Monitor and see what your computer's temperatures and voltages are like?

Jay Gladwell wrote on 7/1/2005, 12:19 PM

IT'S FIXED!

It was the power supply. I installed the new one just over an hour ago and everything's purring like a kitten--no spontaneous reboots.

My thanks to everyone for their support and suggestions!

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JJKizak wrote on 7/1/2005, 3:11 PM

I put dual 300's in my machines about 5 years ago coupled with a Radio Shack 12 vdc relay. Then use the external switched plug to energize the external drive's supplies when using that particular machine. That way the drives don't run all day long for nothing when I am using another machine. I do have to update the master every time a new motherboard goes in with different technology. I give the old ones to my guru buddy and it keeps him happy because I have him download and mail me the Sony updates on his cable dsl because I still have dial-up.

JJK