Computer shutting down randomly

I am fixing a computer for a friend. It seems to shut down without
any reason and then reboot (no BSOD). I reformatted the hard drive,
put in new memory, new video card and new soundcard to bypass the
onboard audio/video. It seemed to work ok, but after about 45
minutes, it shut down.
I clean the CPU fan, checked all the connections and cannot find the
source of the problem.
I have upgraded to SP2 as well, but again - I thought at first it
might have been a virus or software problem, but now I am not so
sure. I am going to run the ASUS probe software and see if the
temperature is fluctuation, but it seemed quite cool.

Any ideas? Does this sound like a motherboard issue or a power supply?

Michael
Thu May 29 20:37:35 PDT 2008

daviddschool wrote:
> I am fixing a computer for a friend. It seems to shut down without
> any reason and then reboot (no BSOD). I reformatted the hard drive,
> put in new memory, new video card and new soundcard to bypass the
> onboard audio/video. It seemed to work ok, but after about 45
> minutes, it shut down.
> I clean the CPU fan, checked all the connections and cannot find the
> source of the problem.
> I have upgraded to SP2 as well, but again - I thought at first it
> might have been a virus or software problem, but now I am not so
> sure. I am going to run the ASUS probe software and see if the
> temperature is fluctuation, but it seemed quite cool.
>
> Any ideas? Does this sound like a motherboard issue or a power supply?

You should look carefully at the motherboard to see if any of the
capacitors are bulging or leaking. I had similar problems and after
examining the motherboard, in my case if was easy as I had a window on
the side of the case, I found a bulging capacitor below the CPU. After
contacting ASUS and getting a replacement board everything has worked fine.
If it doesn't appear that the motherboard is the problem I would check
the temperatures of both the CPU and the video card to see if they are
overheating. After that check the power supply voltages using a program
like Speedfan or a multimeter.

Paul
Thu May 29 21:11:48 PDT 2008

daviddschool wrote:
> I am fixing a computer for a friend. It seems to shut down without
> any reason and then reboot (no BSOD). I reformatted the hard drive,
> put in new memory, new video card and new soundcard to bypass the
> onboard audio/video. It seemed to work ok, but after about 45
> minutes, it shut down.
> I clean the CPU fan, checked all the connections and cannot find the
> source of the problem.
> I have upgraded to SP2 as well, but again - I thought at first it
> might have been a virus or software problem, but now I am not so
> sure. I am going to run the ASUS probe software and see if the
> temperature is fluctuation, but it seemed quite cool.
>
> Any ideas? Does this sound like a motherboard issue or a power supply?

If you need a stress test, try Prime95. This particular version
is for Windows, and will run a test thread per core on a
multicore processor. On the main mersenne.org web site, there
are other versions, such as ones you can run under Linux.

http://www.mersenne.org/gimps/p95v255a.zip

The idea here, is to see whether running a stressful program,
like the torture test of Prime95, causes the computer to
reboot sooner. Prime95 will cause the CPU to draw more power,
highlighting a problem with bad caps on the motherboard, or a
bad power supply.

To monitor the power supply, you could try Speedfan (almico.com).
The hardware monitor chip is not the most accurate thing in the world.
but you could use Speedfan to watch what happens, just when the
Prime95 program starts testing. (Asus Probe should also work.)

http://www.almico.com/speedfan434.exe

Paul

Anna
Fri May 30 09:49:16 PDT 2008


> daviddschool wrote:
>> I am fixing a computer for a friend. It seems to shut down without
>> any reason and then reboot (no BSOD). I reformatted the hard drive,
>> put in new memory, new video card and new soundcard to bypass the
>> onboard audio/video. It seemed to work ok, but after about 45
>> minutes, it shut down.
>> I clean the CPU fan, checked all the connections and cannot find the
>> source of the problem.
>> I have upgraded to SP2 as well, but again - I thought at first it
>> might have been a virus or software problem, but now I am not so
>> sure. I am going to run the ASUS probe software and see if the
>> temperature is fluctuation, but it seemed quite cool.
>>
>> Any ideas? Does this sound like a motherboard issue or a power supply?


"Michael W. Ryder" <_mwryder@worldnet.att.net> wrote in message
news:3EK%j.4144$SV4.2988@bgtnsc04-news.ops.worldnet.att.net...
> You should look carefully at the motherboard to see if any of the
> capacitors are bulging or leaking. I had similar problems and after
> examining the motherboard, in my case if was easy as I had a window on the
> side of the case, I found a bulging capacitor below the CPU. After
> contacting ASUS and getting a replacement board everything has worked
> fine.
> If it doesn't appear that the motherboard is the problem I would check the
> temperatures of both the CPU and the video card to see if they are
> overheating. After that check the power supply voltages using a program
> like Speedfan or a multimeter.


David:
As Michael has indicated it certainly sounds like a hardware-type problem
and any of those major components he mentions could be the problem.

I assume you're working with a desktop PC, so do this...

First, check out the HDD with the diagnostic utility that (hopefully) will
be available from the website of the disk's manufacturer. It's probably not
a defective HDD that's causing the problem based on how you've described the
problem but it's *always* a wise thing to check out the disk in situations
like this.

Assuming the drive checks out OK hardware-wise...

After shutting down your machine, remove (disconnect) all peripheral
devices from the machine including your hard drive(s), optical drive(s),
sound card, etc. Disconnect all storage devices, printers, and any other
devices connected to the machine.

So that all you'll be working with is your motherboard, processor, heat
sink, RAM, video card, and power supply. Better yet, should your motherboard
be equipped with onboard video/graphics capability, disconnect your video
card from the system. Just make sure your BIOS setting (should there be one)
reflects that onboard graphics/video is enabled. (I realize you've
installed a new video card but still have the same problem so the likelihood
is it's not the graphics/video card that's the culprit here, but if the
system does have onboard graphics/video capability it's always wise to test
the system without an auxiliary graphics/video card).

Reconnect your A/C cord and power on the system.

What happens? Do you get a "normal" screen display? No error messages or
strange notations?

Can you access your BIOS without any difficulty at this point and review the
CMOS settings? Can you check the hardware monitor in the BIOS to determine
that all temps are within normal range? Keep monitoring the temps while the
system is running to determine whether there's an overheating problem.

Assuming all is well at this point leave the system powered on for the next
hour or so, continually checking to see if anything untoward shows up,
particularly temperature-wise.

Using your reset button, try powering down & up a few times to determine if
there are any problems there.

Should all appear well at this point this is an indication that there's
nothing wrong with the basic components of your system. While it's not
absolutely definitive that this is so, it's a very strong indication that
something else is amiss - possibly involving an operating system corruption
of some sort.

If it is a hardware problem as it appears to be, the only definitive way to
determine the defective component is through substitution on a
component-by-component basis which of course is obviously a problem for most
end-users.

It doesn't sound like a motherboard problem but it's possible. While I would
lean toward a possible defective power supply it could be something else.
I'm sure you've checked all your data/power cable connections to determine
they're properly connected, right?

If you do track down the cause of the problem and its fix, please keep us
informed.
Anna