Computer switching itself off

rmg1

Hi all

I've been asked to look at a friends machine which has suddenly started switching itself off after about 10 minutes. This started a few days ago.

I initially thought over-heating so I've asked her to run it with the top off (it's a mini-tower) to see if that helped. It hasn't.

I've changed the CMOS battery as it was losing the system time (but I've only done that today).

The odd thing about it (to me) is that it doesn't come back on straight away if you press the power button, but if I switch off the wall socket it's plugged into and switch it back on, the computer starts up for about 10 minutes and then dies again.

There are no warning messages about it switching off unexpectedly, no CHKDSK activity or anything odd like that. It just switches back on as though a proper shutdown had occurred.

I installed a graphics card when she first bought it (in January) as the monitor only has a DVI input but that's working fine.

On the inside of the case, just above where the PSU would be, there are brown marks which correspond to the placement of the vents on the PSU.

I haven't tried starting it in safe mode (which is my next step).

It's running windows XP (can't remember the RAM) and I know it's got AVG 2012 installed (which I haven't got round to swapping for something decent as yet).

I'm open to suggestions on this one.

Lost2

when I had a computer a couple of years ago
I had the same problem with computer starting up then turning off
took it to repair shop and it was the fan he told me that the computer switches it's self off to protect the computer from over heating

chris-j

Could still be overheating. Are the fans running? Fan on cpu not working would cause cpu to overheat or fan in psu not working would cause it to cut out, sounds like psu.

esuhl

It sounds like some safety cut-out is tripping in the PSU... I'd guess that either the system is overheating or the PSU is faulty... Can you test with a different PSU?

johnmc

I've had the same problem in the past. It was the PSU.

Jamie_Cortez

Brown marks above the PSU vents you say?
Sounds healthy..

I would suggest replacing teh PSU with an alternative and test, and if the same result replace the CPU fan, reapply thermal paste and test again.

paddyrg

rmg1 wrote: »

I initially thought over-heating so I've asked her to run it with the top off

You can imagine what my imagination did with that ;-)

Diesel44

This happend to mine, ended up being the thermal paste between the cpu and heat sink breaking down.
It's not a difficult job to do. just watched several utube vids.
Cleaned the old paste and replaced with new.
Still working today.
I think I found the temp high when checking in the Bios.

bertanbudak

Have had this problem too. Thanks so much for the advice guys!

rmg1

Thanks folks.
Don't have a spare PSU of the right type (I don't think).
I'll check the thermal paste (that I do have).

Paddyrg - you need help!!!


::edit::
Another thing that's just occurred to me.
I can see a fan speed for both CPU and system.
The system fan reading is just under 2000RPM but usually comes up in red text.
Don't know if this helps/hinders with diagnostics?

Jamie_Cortez

Red text would signify its hit a warning marker.

Take the fan off clean it, reapply paste as suggested and make sure to reseat it tightly then see if its still the same.