Why does my computer just shut off?

[Jeepwolf]

Every once and awhile my computer just shuts itself off. No reason
whatsoever. It's not overheating, both the power supply and cpu fan
are running. There are no loose wire plugs, or loose memory or other
plugin chips. There are no swelled capacitors. The hard drives pass
scandisk tests. I just recently set the bios to default, except for
turning off all power management.

It's an IBM PIII 1000mhz. I run Win98se and Dos apps, only.
Most of the time it works fine, but every so often it just shuts off.
This usually occurs after it's been turned on for hours. It just did
it a few minutes ago. It was sitting idle for a while, with Win98
loaded and a few websites still on the screen under IE. I sat down
and the second I touched the mouse, it shut off. No blue screen or
anything, just shut off.

I rarely have blue screens and other windows faults, except IE likes
to freeze up, which is why I use Firefox and Opera more often.
Otherwise it's hyst fine till it reboots or shuts off for no reason.

 

[kony]

Every once and awhile my computer just shuts itself off. No reason
whatsoever. It's not overheating, both the power supply and cpu fan
are running.

Do you really know it isn't overheating or are you only
assuming this because the fans are running? It is quite
possible to have it overheat with fans still running,
particularly after several years of running an open flipchip
like your Coppermine P3, especially with generic silicone
based heatsink grease the grease's oil carrier eventually
separates from the solids leaving irregular thermal
conduction.

In other words, if all else fails take off the heatsink,
clean off the old thermal interface material (may require a
petroleum based cleaner if it's the original thermal pad)
and apply a very thin layer of fresh heatsink grease.

There are no loose wire plugs, or loose memory or other
plugin chips. There are no swelled capacitors. The hard drives pass
scandisk tests. I just recently set the bios to default, except for
turning off all power management.

How about swollen capacitors in the power supply?
Suddenly shutting off or resetting is a feature of your
processor, but it is more commonly caused by a failing power
supply. You might unplug the PSU for several minutes then
open and inspect it, and considering the age of the system
it might be time to clean the dust out.

It's an IBM PIII 1000mhz. I run Win98se and Dos apps, only.
Most of the time it works fine, but every so often it just shuts off.
This usually occurs after it's been turned on for hours. It just did
it a few minutes ago. It was sitting idle for a while, with Win98
loaded and a few websites still on the screen under IE. I sat down
and the second I touched the mouse, it shut off. No blue screen or
anything, just shut off.

I rarely have blue screens and other windows faults, except IE likes
to freeze up, which is why I use Firefox and Opera more often.
Otherwise it's hyst fine till it reboots or shuts off for no reason.

You should consider reinstalling IE, and run memtest86+ for
a few hours to check memory. Also run Prime95's torture
test, it's large in-place FFTs setting to check CPU temp and
stability.

I'd place the PSU as suspect #1.

 

[Jeepwolf]

Do you really know it isn't overheating or are you only
assuming this because the fans are running? It is quite
possible to have it overheat with fans still running,
particularly after several years of running an open flipchip
like your Coppermine P3, especially with generic silicone
based heatsink grease the grease's oil carrier eventually
separates from the solids leaving irregular thermal
conduction.

In other words, if all else fails take off the heatsink,
clean off the old thermal interface material (may require a
petroleum based cleaner if it's the original thermal pad)
and apply a very thin layer of fresh heatsink grease.



How about swollen capacitors in the power supply?
Suddenly shutting off or resetting is a feature of your
processor, but it is more commonly caused by a failing power
supply. You might unplug the PSU for several minutes then
open and inspect it, and considering the age of the system
it might be time to clean the dust out.


You should consider reinstalling IE, and run memtest86+ for
a few hours to check memory. Also run Prime95's torture
test, it's large in-place FFTs setting to check CPU temp and
stability.

I'd place the PSU as suspect #1.

Well, I am assuming it's not overheating cuz the fans work, but when I
run my hands down along the heat sink and touch the edge of the cpu,
it's not even warm. I think I may have another power supply around
here that I can swap. I'll have to look. If that dont do it, I will
try the other things you said. I should mention that this never
happened in the summer, even without an AC in the house, and it was
often 90+ in here. Now it's about 66 deg.

Where do I get that software you mentioned?
memtest86+
Prime95's torture test

By the way, I just touched the mouse with my hand, since the question
was asked.

Thanks

 

[CBFalconer]

Every once and awhile my computer just shuts itself off. No reason
whatsoever. It's not overheating, both the power supply and cpu fan
are running. There are no loose wire plugs, or loose memory or other
plugin chips. There are no swelled capacitors. The hard drives pass
scandisk tests. I just recently set the bios to default, except for
turning off all power management.

My bet is a bad memory chip somewhere. Ignore this if you have ECC
memory. If not, get and run memtest86 overnight. If you do have
bad memory you may have problems getting a good copy of memtest86.

Windows has the extremely childish habit of rebooting itself on
some errors, rather that stopping and complaining. I forget how to
turn it off.

 

[kony]

Where do I get that software you mentioned?
memtest86+
Prime95's torture test

Google for "memtest86+" and "Prime95", they're quite
popular.

 

[kony]

My bet is a bad memory chip somewhere. Ignore this if you have ECC
memory. If not, get and run memtest86 overnight. If you do have
bad memory you may have problems getting a good copy of memtest86.

Windows has the extremely childish habit of rebooting itself on
some errors, rather that stopping and complaining. I forget how to
turn it off.

Win2k, XP will reboot on error but win98 generally just
locks up and/or bluescreens. None of them would make a
system shut off from bad memory.

 

[Jeepwolf]

Win2k, XP will reboot on error but win98 generally just
locks up and/or bluescreens. None of them would make a
system shut off from bad memory.

I was thinkinhg memory problems but I did not think it would just shut
off either. Thi computer is one that shuts off when, for example I
install a program that wants to reboot, the computer shuts off, stays
off for maybe 30 seconds and turns back on. I have windows set to
always shut down to dos, because I run a dos based phone number
database. plus I always run a batch file that removed all the cache,
cookies and temp files from the whole computer. So if windows screwed
up, it would either freeze, or else boot to dos. Instead it just
shuts down completely and in one second. It leaves the green led
pilot light on next to the power switch, but the power switch does not
restart it, or shut it off. I have to shut off my power strip or
unplug it and replug it before it will run again. There is no
indication before this happens, it just shuts off.

As far as downloading that memory tester prgm, that wont be a problem.
I just downloaded several freeware programs that were from 1 to 7 megs
and they all worked.

Thanks to all.

 

[kony]

I was thinkinhg memory problems but I did not think it would just shut
off either. Thi computer is one that shuts off when, for example I
install a program that wants to reboot, the computer shuts off, stays
off for maybe 30 seconds and turns back on.

I suspect you are using terms that are leading to a
misunderstanding of what the system is doing. Shut off
means off, while you seem to be describing something that is
not shutting off but rather reboot and reset.

Having it take a long time to reset and initialize could be
a lot of things from OS failing to exit gracefully to an
instability in the board or bios due to bugs or damage or
defect or bad PSU.

Did the system previously work correctly in this same
situation? If so, you might try installing windows again in
case it is the operating system, but otherwise I would still
suspect the power supply or possibly motherboard. If you
have a multimeter you might check PSU voltages. If you have
changed anything about the system just prior to the onset of
the problem you might change that back to the way it was
previously.

I have windows set to
always shut down to dos,

Exit to DOS.

because I run a dos based phone number
database. plus I always run a batch file that removed all the cache,
cookies and temp files from the whole computer. So if windows screwed
up, it would either freeze, or else boot to dos.

Boot is what a system does after bios initialization.
It is not what windows ever does if it screws up, unless you
mean that you had a boot menu upon which you set DOS to be
the default OS it boots to without user intervention.

Proper terminology is essential for us to understand what is
happening.

Instead it just
shuts down completely and in one second.

The term "shut down" may not be good to accurately convey
what is happening.

Here are some things it might do:

1) Lockup

2) Reset (which means it begins the POST and tries to boot,
even if it takes a long time to do so, or it is so instable
that it wants to reset and halts before it can reboot.

3) Shut off or turn off, no power to the system anymore,
lights out and fans stop.

Describing exactly what you see from the very first
indication of the problem until the very last state will
help us understand what it is doing.

It leaves the green led
pilot light on next to the power switch, but the power switch does not
restart it, or shut it off. I have to shut off my power strip or
unplug it and replug it before it will run again. There is no
indication before this happens, it just shuts off.

So it isn't shutting off, it is still running, just not
running anything of use (like the POST routine to reboot or
the OS error bluescreens).

As far as downloading that memory tester prgm, that wont be a problem.
I just downloaded several freeware programs that were from 1 to 7 megs
and they all worked.

???

I don't understand why you are describing downloading some
other program instead of running memtest86+ to check the
memory.

If the system is quite instable you might have some memory
problems but if they were bad enough that it prevented even
the system reset and initialization, it should be bad enough
to prevent it turning on and doing that the first time as
well as running windows until the point where a reset took
place due to an app or user intervention.

What you are describing sounds like hardware instability but
you might also see if it is stable running an alternate OS,
like a Ubuntu LiveCD, which once made will allow the system
to boot from and run from that CD... but it is a fairly
large download at (if I remember correctly) about 700MB, and
of course will need to be burnt to a CD or DVD.

 

[Jeepwolf]

I suspect you are using terms that are leading to a
misunderstanding of what the system is doing. Shut off
means off, while you seem to be describing something that is
not shutting off but rather reboot and reset.

Having it take a long time to reset and initialize could be
a lot of things from OS failing to exit gracefully to an
instability in the board or bios due to bugs or damage or
defect or bad PSU.

Did the system previously work correctly in this same
situation? If so, you might try installing windows again in
case it is the operating system, but otherwise I would still
suspect the power supply or possibly motherboard. If you
have a multimeter you might check PSU voltages. If you have
changed anything about the system just prior to the onset of
the problem you might change that back to the way it was
previously.


Exit to DOS.



Boot is what a system does after bios initialization.
It is not what windows ever does if it screws up, unless you
mean that you had a boot menu upon which you set DOS to be
the default OS it boots to without user intervention.

Proper terminology is essential for us to understand what is
happening.



The term "shut down" may not be good to accurately convey
what is happening.

Here are some things it might do:

1) Lockup

2) Reset (which means it begins the POST and tries to boot,
even if it takes a long time to do so, or it is so instable
that it wants to reset and halts before it can reboot.

3) Shut off or turn off, no power to the system anymore,
lights out and fans stop.

Describing exactly what you see from the very first
indication of the problem until the very last state will
help us understand what it is doing.



So it isn't shutting off, it is still running, just not
running anything of use (like the POST routine to reboot or
the OS error bluescreens).



???

I don't understand why you are describing downloading some
other program instead of running memtest86+ to check the
memory.

If the system is quite instable you might have some memory
problems but if they were bad enough that it prevented even
the system reset and initialization, it should be bad enough
to prevent it turning on and doing that the first time as
well as running windows until the point where a reset took
place due to an app or user intervention.

What you are describing sounds like hardware instability but
you might also see if it is stable running an alternate OS,
like a Ubuntu LiveCD, which once made will allow the system
to boot from and run from that CD... but it is a fairly
large download at (if I remember correctly) about 700MB, and
of course will need to be burnt to a CD or DVD.

What it's doing is this one (copied from your reply)
3) Shut off or turn off, no power to the system anymore,
lights out and fans stop.

EXCEPT that green LED is still on. But no fans, no hard drive
spinning sound, etc. It's basically shut off, excerpt for that LED
next to the power switch.

Yes, this computer worked fine for a half year since I got it. This
started about a month ago. It's been running fine since I posted the
initial message yesterday morning, which means about 26 hours. I have
not rebooted or shut it off since. The problem is real random.

 

[kony]

What it's doing is this one (copied from your reply)
3) Shut off or turn off, no power to the system anymore,
lights out and fans stop.

EXCEPT that green LED is still on. But no fans, no hard drive
spinning sound, etc. It's basically shut off, excerpt for that LED
next to the power switch.

That seems most likely a power supply failure.

Yes, this computer worked fine for a half year since I got it. This
started about a month ago. It's been running fine since I posted the
initial message yesterday morning, which means about 26 hours. I have
not rebooted or shut it off since. The problem is real random.

If you don't have a spare PSU of adequate quality and
capacity for the system, you might buy one from someplace
with a good return policy then if you try that andn it
doesn't work, at worst you are only out the return shipping
and restocking cost, although a replacement PSU for such an
old system doesn't usually cost very much as they used far
less current back then.

 

[Michael T.]

Where do I get that software you mentioned?
memtest86+
Prime95's torture test

This memory test from Microsoft used to work for me.
http://oca.microsoft.com/en/windiag.asp#top

 

[larry moe 'n curly]

Every once and awhile my computer just shuts itself off. No reason
whatsoever. It's not overheating, both the power supply and cpu fan
are running. There are no loose wire plugs, or loose memory or other
plugin chips.

What about corroded plugs? Try unplugging and reseating each plug and
the memory modules. Sometimes the power plug for the hard drive works
loose and needs to be pinched tight -- slightly.

There are no swelled capacitors.

Capacitors can go bad before they start to swell. And what about the
capacitors inside the PSU? BTW, don't open up the PSU without first
unplugging the AC power cord and waiting at least 20 minutes, and
don't just turn off the AC switch. In many PSUs at least one of the
heatsinks is connected directly to high voltage, about 350 VDC.

It's an IBM PIII 1000mhz. I run Win98se and Dos apps, only.

Did you run SFC (System File Checker) or something like Norton Windows
Doctor (not Disk Doctor)?

 

[Michael T.]

That seems most likely a power supply failure.

I tend to agree, especially since you make no mention of the BSOD (blue
screen of death) before it dies.

For what it's worth here is a good resource for troubleshooting Windows 98
shutdown problems.
http://aumha.org/win4/a/shutdown.htm

Does Windows 98 have Event Viewer? I seem to recall that it does if you go
to the Control Panel and click Administrative Tools. I have used this in the
past to attempt to determine which app or service may have failed when the
crash occurred.

 

[kony]

I tend to agree, especially since you make no mention of the BSOD (blue
screen of death) before it dies.

For what it's worth here is a good resource for troubleshooting Windows 98
shutdown problems.
http://aumha.org/win4/a/shutdown.htm

Does Windows 98 have Event Viewer? I seem to recall that it does if you go
to the Control Panel and click Administrative Tools. I have used this in the
past to attempt to determine which app or service may have failed when the
crash occurred.

There's no Administrative Tools in win98, no Event Viewer.
There may be some kind of logging of individual things, for
example I recently saw an ndislog.txt that informed that a
NIC was out of resources, but these logs aren't centralized.
Even so, it wouldn't hurt to do a Find->Files for files
modified recently to see what turns up beyond what'd been
expected to be modifited.


The problem with win98 is the fragility in that if one part
crashes, often the whole ship 'sinks, so there might be
nothing working to report an error if one occurs.
Fortunately Win98 also has a lot less going on in the
background so the perpetual minor errors Win2k, XP, and
Vista encounter aren't so devistating to the point that it
won't run at all.

Another option that requires less effort that reinstalling
or clean installing win98 again, or making and running a
Linux LiveCD (like Ubuntu) would be to just leave the system
sitting in the bios menu and see if it eventually shuts
down. If it doesn't that's not necessarily telling of
anything but if it does, it has ruled out the OS (or at
least, the odds are the OS was not the initial problem
though after running instabily there could be some data or
file corruption that then effects windows running properly.

 

[Brian Cryer]

Every once and awhile my computer just shuts itself off. No reason
whatsoever. It's not overheating, both the power supply and cpu fan
are running. There are no loose wire plugs, or loose memory or other
plugin chips. There are no swelled capacitors. The hard drives pass
scandisk tests. I just recently set the bios to default, except for
turning off all power management.

It's an IBM PIII 1000mhz. I run Win98se and Dos apps, only.
Most of the time it works fine, but every so often it just shuts off.
This usually occurs after it's been turned on for hours. It just did
it a few minutes ago. It was sitting idle for a while, with Win98
loaded and a few websites still on the screen under IE. I sat down
and the second I touched the mouse, it shut off. No blue screen or
anything, just shut off.

I rarely have blue screens and other windows faults, except IE likes
to freeze up, which is why I use Firefox and Opera more often.
Otherwise it's hyst fine till it reboots or shuts off for no reason.

I don't think this has been suggested before (apologies if it has), can I
assume that the inside of the case isn't dusty? If there is a fan on the cpu
then check that it isn't clogged with dust (I doubt that it is given that
you said the heat sink didn't feel warm). It might be worth getting a vacuum
cleaner out and giving the power supply a clean best you can - sounds daft I
know but give it a try.

 

[GT]

it just
shuts down completely and in one second. It leaves the green led
pilot light on next to the power switch, but the power switch does not
restart it, or shut it off.

That sounds a little like a standby state gone wrong! Probably a failing
component. Have you recently added any new devices to the system? Perhaps
the power supply is running overloaded.

 

[Plato]

Every once and awhile my computer just shuts itself off. No reason
whatsoever. It's not overheating, both the power supply and cpu fan

How do you know it's not overheating?

 

[Plato]

My bet is a bad memory chip somewhere. Ignore this if you have ECC

And very often overlooked as the "culprit".