Why does my computer shut itself off without a request?  The power
suddenly shuts off without any warning and no discernible pattern. It
shuts off just as if the user was to use the POWER switch or button. 

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Request for Question Clarification by webadept-ga on 27 May 2002 09:31 PDT

What kind of computer? and what Operating system? (Mac, Windows,
Linux, Be) There are lots of reasons for this, and not all of them
bad.

Does it shut off while you are using it, or after it has been sitting
untouched for a while?

webadept-ga

Hello:

Your problem can be due to many reasons, maybe the power suply of your
computer, maybe the power switch is not well attached to the
motherboard, etc...

I have been looking for problems like yours and in this message:

http://www.visorvillage.com/boards/Bugs/messages/1422.html

Which tells the user to download the Windows 98 Second Edition
Shutdown Supplement at
http://www.microsoft.com/windows98/downloads/contents/WURecommended/S_WUFeatured/Win98SE/

You don't say which operating system you are running and what kind of
machine you have, so let's make some more research. I supose is your
personal computer and you don't have installed any kind of software to
limit the access to your PC.

I recommend you to perform a virus scanner looking for viruses and
trojans, you can do it for free here:

Symantec Security Response
http://security.norton.com/default.asp?langid=us&venid=sym

Also you have to be careful with the temperature of your computer, if
your computer is relatively new you can look this value in the BIOS of
your PC, when the system starts press Supr (may vary from computers)
and enter in the BIOS, there must be a place to look this value. Check
your motherboard documentation to know where is this information and
what are recommended values. For example, if you have a 7200 rpm disk
without fan attached to it, this can make the temperature inside the
PC case too high.

"If you have a system that seems to run fine, then just shuts itself
off after a half hour or so, check out the operating temperature of
the CPU. See that the fans are working on the power supply and the
CPU's heatsink."

Your computer's case
http://www.pccomputernotes.com/computer_case/cases1.htm

"It may have been because of a power "hiccup". It's not exactly a
power surge, or a dip, but it's enough to disrupt the computer itself.
Result? Your system reboots in no time flat - or goes into an error
screen (commonly referred to as "the blue screen of death"). When this
happens, there's still a chance that your computer will be able to
recover the file you were working on, but it will most probably be
fragmented or in fragments. If you already have a surge protector and
a UPS, then check the power cord itself for looseness or breaks."

Reboots and signal problems
http://www.getasia.com.ph/getasia/tech_ph.nsf/Content/10022001qa

I hope this could help you, if not, request a clarification and I will
continue trying to solve your problem.

Regards.

Have you checked your processor fan?  Many computers will
automatically shut down if the processor fan stops.  Could be a sign
of your fan getting ready to give up.  It's a $5 part, easily
replaced, and certainly worth a look.

If metal screws instead of plastic ones were used to mount your
motherboard to your computer case, that might be your problem.  The
screws are usually very close to some of the wiring on your
motherboard, and if they touch, it may give too much "ground", and
reboot your computer.

Is the sun shining on the computer? You can check the CPU temperature
by starting and going into the bios.
Is the power cable slightly loose?
Did you check your power saving settings?
Maybe buying a new power supply solves the problem? Maybe ask the guy
in the shop and bring with you your computer specifications.
It could also be the reset button is a bit broken.
Do you have virus protection software installed?
Are some cards loosely connected?

Also of note is the Windows XP problem (or feature as Microsoft call
it). Basically, where previous versions of Windows would display a
BSOD (Blue Screen Of Death) on a program error, or simply display a
"Progam will be shut down" box, XP will reboot the computer instead in
an attempt to protect itself. This default behaviour can be changed in
the advanced Admin part of the Control Panel. I read an article about
it on CNET a few weeks ago here which explains the problem in more
detail - [ http://home.cnet.com/software/0-6688749-8-9696202-2.html?tag=st.sw.6688749-8-9696202-1.txt.6688749-8-9696202-2
]. Just a thought...

I had this problem with my computer when I lived with my parents. It
was so wierd, there didnt seem to be anything wrong with the computer
and it didnt always happen. It would turn itself off about 4 mins
after I'd turned it on.
When I put it on after that it'd be ok. One time that i recall it
refused to turn on for like 5 mins, that was worrying, but it
recovered :)

I have the same computer in my own house now and it doesnt happen.
I've come to the conclusion that since there's nothing wrong with the
computer, I would know if there was - I have it on 24/7 now, that the
problem was to do with an old extension lead that I was using. Tho
strangely the problem didnt affect my hifi that was plugged into as
well.
I don't really know much about electrical stuff, but I would suggest
you check any extension lead/power cables/supply if poss that you are
using.

hth

browolf

I've heard this story before, but it's rarely a defect in the
computer. I see two plausible causes for your problem:

1. Your power is unreliable (you'd probably notice your lights
flickering). If you have reason to believe that it could be the fault
of power spikes or outages and don't see yourself moving soon, get a
UPS (Uninterrupted Power Supply).

2. This is the more likely cause: Many computers built over the last
ten years or so come with energy saving features. Most computers limit
these features to a "sleep" mode, which requires some keyboard and/or
mouse activity to wake it. Some Macintoshes, however, go a step beyond
that. Either in the "Auto Power On/Off" or the "Energy Saver" control
panel (depending on your OS), you can set up your computer to turn off
at a specific time or after a certain period of inactivity. This is
easily corrected by modifying the settings in that control panel.

If neither of these solutions solve your problem, you may want to
perform a clean system install. Once you've ruled out software, then
you can start looking at hardware problems.

Finally, in response to those who blame your problem on CPU
temperature - if a processor overheats sufficiently to turn the
computer off, it probably won't turn on ever again.

It's not the case that it can't be the CPU fan.

I've personally had two PC's where the fan has gone and they both
exhibited his behaviour.

I've also had two mates who's PC's rebooted regularly for no apparent
reason, and both were solved by adding a new CPU fan.

<i>If</i> your machine starts up with a fairly loud fan sound, then
that's the very first place I'd look.

Also, contrary to what you might think, cooling works better with the
case ON the machine, not OFF it. It's due to the way the air is
circulated.

I had a problem similar to this on my computer years ago (it has
happened this, but the solution is never more than 5 minutes away).

The problem I was experiencing was because of the fan on the CPU - I
didn't have to replace it though. All I did was got a straw and blew
air into the fan to get rid of all the dust. Once all the dust is
gone, the computer seems to work fine.

The only other time my computer has continually frozen was when my
hard-disk was about to go. The only solution to that was to get
another hard-disk.

Hope this helps!

If you have an Athlon XP Chip and PC133 memory, change the memory.

There are known issues with specific brands of memory which cause this
sudden switching off.

Usually when it is the CPU overheating the computer will exhibit weird
behaviour before it actually shuts off. So my guess would be the
powersupply, the nic card if you have the wake on lan plug attached
variations is power can cause your computer to shut off or possibly if
you have a backup UPS that has a bad battery you will get shut off and
then back on when it runs its test.