Spontaneous system reboots

Steve DeLassus asked me the other day what I would do to fix a PC that was rebooting itself periodically. It’s not him who’s having the problem, he says, it’s someone he knows. He must be trying to show up someone at work or on the Web or something.
So I gave him a few things I’d check, in order of likelihood.

Static electricity. A big static shock can send a system down faster than anything else I’ve seen. Keep a humidifier in the computer room to reduce static electricity. If you’re really paranoid, put a metal strip on your desk and connect it to ground (on your electrical outlet, not on your PC) and touch it before touching your PC. Some people metalize and ground part of their mouse pad. That’s a bit extreme but it works.

Power supply. This is the big one. A failing power supply can take out other components. And even if you have an expensive, big-brand box like a PCP&C or Enermax, they can fail. So I always keep a spare ATX power supply around for testing. It doesn’t have to be an expensive one–you just want something that can run the machine for a day or two to see if the problem goes away.
Overheating. Check all your fans to make sure they’re working. An overheated system can produce all sorts of weird behavior, including reboots. The computer we produced our school newspaper on back in 1996 tended to overheat and reboot about 8 hours into our marathon QuarkXPress sessions.

Memory. It’s extremely rare, but even Crucial produces the occasional defective module. And while bad memory is more likely to produce blue screens than reboots, it’s a possibility worth checking into. Download Memtest86 to exercise your memory.

CPU. If you’re overclocking and experiencing spontaneous reboots, cut it out and see what happens. Unfortunately, by the time these reboots become common, it may be too late. That turned out to be the case with that QuarkXPress-running PC I mentioned earlier. Had we replaced the fans with more powerful units right away, we might have been fine, but we ended up having to replace the CPU. (We weren’t overclocking, but this was an early Cyrix 6×86 CPU, a chip that was notorious for running hot.) Less likely today, but still possible.

Hard drive. I’m really reaching here. If you’re using a lot of virtual memory and you have bad sectors on your hard drive and the swapfile is using one or more of those bad sectors, a lot of unpredictable things can happen. A spontaneous reboot is probably the least of those. But theoretically it could happen.

Operating system. This is truly the last resort. People frequently try to run an OS that’s either too new or too old to be ideal on a PC of a particular vintage. If the system is failing but all the hardware seems to be OK, try loading the OS that was contemporary when the system was new. That means if it’s a Pentium-133, try Win95 on it. If it’s a P4, try Windows 2000 or Windows XP on it. When you try to run a five-year-old OS on a new system, or vice-versa, you can run into problems with poorly tested device drivers or a system strapped for resources.

Another good OS-related troubleshooting trick for failing hardware is to try to load Linux. Linux will often cause suspect hardware to fail, even if the hardware can run Windows successfully, because Linux pushes the hardware more than Microsoft systems do. So if the system fails to load Linux, start swapping components and try again. Once the system is capable of loading Linux successfully, it’s likely to work right in Windows too.

Troubleshooting advice: When you suspect a bad component, particularly a power supply, always swap in a known-good component, rather than trying out the suspect component in another system to see if the problem follows it. The risks of damaging the system are too great, particularly when you try a bad power supply in another system.

And, as always, you minimize the risks of these problems by buying high-quality components, but you never completely eliminate the risk. Even the best occasionally make a defective part.

8 thoughts on “Spontaneous system reboots

  • March 27, 2002 at 1:08 pm
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    Installing Office 97 on Windows 2000 did it for me, random reboots. Uninstalled it and no more problems. True, MS never said Office 97 was supported by Windows 2000. The only thing that has ever crashed NT4 or W2K for me was MS applications (except the failed hard drive), go figure.

  • March 27, 2002 at 2:36 pm
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    Regarding your troubleshooting advice (don’t put the bad component into good equipment), that reminds me of a story. A new mainframe operator who had destroyed a removable hard disk by opening the door and touching the rotating media. When the service tech had finished replacing the drive, he asked the operator what had happened. "All I did was to touch the disk like this . . . ", which resulted in another destroyed disk.

    Moral of the story, in agreement with Dave’s advice: Don’t let potentially harmful components near good equipment. Applies equally to silicon-based and carbon-based components.

  • March 27, 2002 at 3:36 pm
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    Steve, has that mainframe operator appeared on the Darwin awards? Seems like someone whose last words could be "hey, y’all! Watch this!".

  • March 27, 2002 at 5:13 pm
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    MS Office actually makes more changes to the system than Internet Explorer, so Office-related problems shouldn’t surprise anyone.

    That said, I’ve done W2000/Office 95 installations before, so sometimes you get away with it. And I prefer 95. It was bloated, but it’s the least bloated 32-bit Office.

  • March 27, 2002 at 8:40 pm
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    I had a system that kept rebooting, usually in the late evening after I’d been using it for a while and working the system over hard.

    It was the Powersupply. I had a 230W job in it, a no name at the time, and once I popped in a Sparkle 300W unit, I’ve never had trouble like that again. At the time, the Sparkle unit I bought was the one PCPower&Cooling was using.

  • February 9, 2003 at 9:56 pm
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    how can I reformat my hard drive manually? I have a new hard drive and want to add it to my emachine600. It came with a seagate 20GB, and I am replacing it with a Western Digital 60gb, but I want to reset my computer to orininal values.

  • February 10, 2003 at 10:42 am
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    You can install the harddrive as a slave drive to your current drive. Start up your operating system and reformat the drive with whatever tools your system has. In Windows 2000 that would be under Control Panel, Administrative Tools, Computer Management, Disk Management. You can then copy your personal files to the new drive. Shutdown. Install the slave drive as master and put your operating system disks in the appropriate drive. Reinstall your operating system. MS Windows should not touch any files you copied over unless they are system files. Hope this helps.

  • December 31, 2003 at 7:48 am
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    My ibm compatible keeps rebooting itself periodically. It has been working fine for 1 year now and all of a sudden 4 days ago it just started this. I have not put anything new on the system. Doing all the same email and google searched I have alwasys done. What can i do.

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