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PC switches itself off and I need a solution

Dec 21, 2005 4:44AM PST

Windows XP Pro SP2 (media center 2004) Pentium 4 306 GHz 512 ram.
In the last month my PC has started to switch itself off in the middle of certain tasks. When it does my PC power switch will not work, and I have to switch the machine off at the power socket. I wait a couple of minutes, switch on at the power socket, and am reconnected without a problem. But the task in hand has of course aborted without any apparent evidence of it ever having taken place, any diagnostics, and no restart opportunity.

The problem was first experienced when my son, downloaded a version of Civilision 2. As soon as the problem occurred, I deleted the game. But the problem started to re-occur

Subsequent examples of tasks in hand when I experience this ''switch off'' are:

1) Halfway through ripping a CD
2) Running a full scan using Antivir - trying to trace whether this was a virus.
3) Running a full scan using Adaware - trying to trace whether this was malware.
4) Most recently - today - I downloaded a trial version of System Mechanic 6 - to see whether there may be a hardware or software malfunction. I successfully used it to analyse my hard disk - no problems detected and no switch off. I then decided to use the defrag tool, and the PC ''switched off'' 23% of the way through mapping my C drive.

Otherwise my system is running without problem but I am nervous and am at a loss to understand what the cause might be, whether software or hardware - how to diagnose it, and how to repair it.

Can anyone help - point me at a means of diagnosis without the risk of ''switch off'' - and any ideas on how to correct it.

all contributions gratefully received.

Discussion is locked

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The usual issue is heat.
Dec 21, 2005 4:57AM PST

The complaint and symptoms are classic cooling issues. Try this. Remove the case cover and try it again. If the issue vanishes or nearly vanishes be sure all fans are running, and nothing has a layer of lint or dust on it.


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The usual issue is heat
Dec 21, 2005 6:04AM PST

thankyou I wondered whether heat was the issue, I had hoped to find some software tool that could somehow measure this (this may be cloud cuckoo land) cos I have no idea how it could do that. I will follow your advice a bit nervously, as I havent taken the cover off before, but a unused drive door has been loose for a long time and dust could well be accumulating. Does simple dusting solve the immediate problem , and fastening the drive door prevent re-occurence?


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Said heat measurement tools exist but fail. Here's why.
Dec 21, 2005 6:10AM PST

Most of them will give you the readout of the CPU temp, then maybe something else. The problem is that the PC has many more components which are not equipped with heat sensors. This is why I take the cover off and make sure the fans are good and heatsinks are clean.

The cover is left off till we resolve the issue.

Your choice of course.


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heat measurement tools
Dec 22, 2005 3:10AM PST

Bob and others
I intend to decase my PC and clean up - what sort of dust cloth should I use? I am holding back only because of the time of year and a plague of highly active very interested small would-be mechanics (the kids).

In the meantime I downloaded a couple of what appear to be useful diagnostic tools - MBM 5 freeware - and Hot Cpu tester pro lite. MBM currently sits on the task bar and shows current case and CPU temperature (and sensor 3 but at moment dont understand that). Current PC temp is 55. I ran Hot CPU tester out of curiosity and this is what it does -

'' The testing modules intentionally overload all components to the maximum limits to exhibit their integrity.''

The PC switched off, whilst running these diagnostics a split second after the PC temperature reached 56 centigrade . I thought the limit was 70 centigrade. Could this mean that it is flipping out too early and if so what can I do. Ive looked in BIOS but cant see where I can control the PC temp limits.

Could the above indicate a different problem?

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That's a small window into the issue.
Dec 22, 2005 3:16AM PST

You reported just one temperature. I think you understand the issue better now.

I use a simple damp paper towel to get the dust off the bottom of the case. Compressed air for the heatsinks.


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Thanks problem solved
Dec 27, 2005 5:30AM PST

Thanks Bob
In a unexpected lull during the christmas festivities, and the kids attention elsewhere, I took the cover off and carefully hoovered (narrow nozzle) the all too obvious dust. I also carefully cleaned the fan blades with cotton tips. I ran it with the cover off and its has never run better! or quieter!

I downloaded an excellent freeware utility Speedfan from via This enables me to measure all the temperatures in my PC and automatically control the fan speeds.

Anyway my previous regular high of 79-80 centigrade is now a comfortable 47-50 - with the temperature controlled via speedfan. I have run intensive tasks on the PC and have not experienced again the unexpected shutdown.
I will keep Speedfan as a temperature monitor on my task bar and should it start to go up, I will know what to do. I will also reposition my PC, as it was trapped between a thick wall and the side of the desk. I will also dust it inside at least every six months.

Bob (and the others) thanks for your help and a happy new year.

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laptop switch itself off.
Feb 24, 2010 7:26PM PST

Toshiba the make of the notebook
windows xp
intel core 2 duo
150 gig hard disk
1 gig memory

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No question?
Feb 24, 2010 8:37PM PST

This to a post from 2005 with no question has me reply that you should start a new thread. If you are having the issues noted in this post, be sure to read how others solved it.

Locking this old discussion.

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I agree
Dec 21, 2005 9:22AM PST

Im going to have to agree with the guys, the computer may be set to turn itself off when the cpu detects a certain temperature however this usually incures a warning, the way too check this is to hit del on startup and enter the bios, in their you will find such options for configuration of the heat settings, if this doesnt help feel free to email me at and i will personally help you.

Here To Help

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I agree
Dec 21, 2005 4:38PM PST

Thanks a lot for your offer, and I may well take it up.

I suspect as Bob says the covers must come off, so I can check fans etc. Probably should be done anyway - is this straightforward - should I backup key data first?

My nervousness is that covers and BIOS are untried technical areas for me - and I dont want to do (more??) damage. I also ran a Belarc test yesterday and the hard drive tested SMART healthy. There are no other indications of problem, PC doesnt make funny noises, it feels cool to the touch. However I am also worried that I am storing up a major problem - PC mechanical breakdown, apart from the fact that certain types of job may not be possible to run. Could it be malware as Maggie62 suggests from her experience. I have run a quick Microsoft Anti Spyware Beta - and it completed properly with nothing indicated.

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It's yearly maintenance.
Dec 21, 2005 11:47PM PST

I do such myself since shop charges are in the 100 buck range.

About backup. We all backup what we can't lose.


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computer shutdown
Dec 21, 2005 1:37PM PST

I am NO computer expert, but I had to respond, because I went through the very same thing, except it was caused by my printer. First delete all of the files ,etc. then download Ewido Security Suite.(it's free) It will take care of your problem. You will have to run it every time you turn your computer back on. When it alerts you that it has found something, it will ask if you want to remove it. Let it remove everything it finds. I had to run it about six or seven times, because my computer kept shuting down. if yours is the same thing as mine, you have some malware. I never would have known to do this, but someone told me, so I'm passing it along to you. Hope it works!