Spontaneous Reboots Except in Safe Mode

December 10, 2007 12:20 AM

Why is my computer spontaneously rebooting, immediately or very soon after booting up?

I've read previous questions, which suggest mostly hardware related issues like a faulty PSU or memory. However, the problem does not occur when I boot into safe mode. I have not changed anything about my computer in recent days or weeks--no new software; no new hardware. I had been away from home for maybe two weeks and had not booted it up for that period upon discovering this problem. A System Restore to the most recent available restore point (a couple of weeks ago, as the computer had not been turned on any more recently) did not solve the problem.

Some change must have occurred in hardware or software that is used in normal operation but not in safe mode, and the change was not my doing...ideas?

posted by holympus to Technology (8 answers total)

I would be inclined to think it's a heat issue - spontaneous reboots are often heat issues. Perhaps safe mode pushes your processor less hard, and thus allows it to run cooler, than "dangerous" mode. Check your CPU fan is spinning properly, and that your case fan and its outlet are clear of dust and lint.

Assuming you're running Windows XP (technical questions would really be improved if people told us the OS they're using!), another thing you can do is change the Autorestart setting to see if the reboot is hardware, or software (the latter being more likely to force a BSOD). Right click on "My Computer", select "Properties", click the "Advanced" tab and the press the "Settings" button in the "Startup and Recovery" section. Ensure that "Automatically Restart" is not checked.
posted by benzo8 at 12:53 AM on December 10, 2007

This could be a driver issue. Safe mode leaves out a lot of your drivers and uses the simpler default drivers that ship with XP. Drivers do get corrupted more often than you might expect. I used to have a lot of people having problems with their printer drivers getting corrupted. Reinstallation of the driver always did the trick.
posted by MasterShake at 1:06 AM on December 10, 2007

Overheating, probably. Have you set your graphics drivers to persist overclocking settings? The video card may lock up and force a system reboot trying to reach those values. This happens if you have set it to very high overclocking and the cooling system gets clogged with dust. Settings that work for weeks or months now result in overheating and crash.

PSU may be an issue. As benzo8 said correctly safe mode is less demanding on video card, CPU and other subsystems, so the computer will draw less power. Normal startup may just draw a little bit too much for the damaged PSU and leads to system crash. I had something similar with damaged capacitors on the main board - the system worked nicely under little load and crash hard whenever the load increased. You may want to check those too, if this is an old system.

You could give us some more information about the hardware. CPU, video card, sound card...?

BTW, I had a similar experience with a broken video card once (water damage from a leaking water cooler system). It would boot up in VGA mode but crash once you increased resolution.
posted by Nightwind at 1:11 AM on December 10, 2007

Check your computer for viruses. There used to be one which rebooted the computer after a couple of minutes. I think this was using an exploit which may not exist on Windows XP.

You should also update your OS.

The fact that it didn't happened before you went away does not necessarily exclude those.

See also how to turn off Auto Reboot in XP (when critical error is detected):
- Right click on My Computer
- Select Properties
- Select the Advanced Tab > Startup & Recovery section
- Select the Settings button
- Uncheck "Automatically restart" Apply".
This will give you a blue screen with the error message rather than rebooting the computer.
posted by rom1 at 2:51 AM on December 10, 2007

Have you cracked open your case? A thin layer of dust on the components inside is often enough to cause over heating. Perhaps the dust accumulated during the break period. A can of compressed air will solve that problem quickly enough.
posted by oddman at 4:04 AM on December 10, 2007

This happened to me recently when a case fan went out.
posted by i_am_a_Jedi at 4:23 AM on December 10, 2007

PSU may be an issue. As benzo8 said correctly safe mode is less demanding on video card, CPU and other subsystems, so the computer will draw less power. Normal startup may just draw a little bit too much for the damaged PSU and leads to system crash.
posted by Nightwind at 4:11 AM on December 10 [+] [!]

Seconding this, but also keep in mind PSUs do lose power over time. Yours might have lost enough that it can no longer power everything in the system and thus needs replacing.

Try disconnecting some non-critical devices (CD/DVD drives, floppy, additional hard drives, unnecessary cards, etc) and see if the problem persists without booting into safe mode.
posted by Ziggy Zaga at 4:53 AM on December 10, 2007

Bad memory (Safe mode worked fine!! The memory was bad in the very top of my 1.5gigs. Run memtest or at the very least turn on memory checking in your bios.)
ATI Display drivers and Windows Vista
Incompatible USB devices and Windows Vista (i.e. Motorola phone, certain Lexmark printers)
SATA Drivers and Windows Vista
ZIP drives and Windows Vista
Windows Vista and Windows Vista

Often, turning off the automatic re-boot still won't give you the error, just a blank blue screen. Looking in the Event logs (application, system and hardware) can sometimes give you the answer but mostly you'll have to run through all of your peripherals first and search for "BSOD VISTA (PERIPHERAL MODEL)" without the quotes. I've had all of the above happen to me. I'm sure there's a hundred more ways to get a blue screen and I hope I don't get to find out what any more of them are. They appear to be random, btw and other times can be triggered by windows updates. Installing the DotNET 3.5 beta did it to me in addition to those other things I listed.
posted by IronLizard at 1:23 PM on December 10, 2007