Why does my computer completely shut down without being instructed to; it has happened 4 times in the last month, any suggestions?

One of the most common culprits is overheating. When the fans inside the computer stop operating properly the components inside get too hot. In order to prevent permanent damage the computer shuts itself down. This could be caused by broken fans inside the computer, or just a build-up of dust inside the case.

Does it shut down instantly, like you pulled the plug? Or as if you instructed it to, closing windows, asking if you want to save open documents, etc?

The computer may have a log mentioning the reason for each shutdown, which someone could go check. Other reasons (besides gggritso’s suggestion of overheating, which is one common one, as he wrote) can include OS’ such as Windows connected to the Internet checking and discovering an update that is mandatory and requires the computer to restart to take effect – there may be a setting available to reduce how likely that will happen.

What OS do you use, and how is it updated? When Windows installs updates it often forces a reboot. What form factor has it? If it is a laptop, consider putting it on a good cooling pad. If it is in a tower, consider a better power supply/cooling mechanism.

It shuts down instantly not as if instructed to… I’ll check out the overheating possibility…um, what does OS stand for?... I choose when to install updates, it does not happen automatically… I know who to ask about a possible log which may register the reason behind the shutdown… thanks for all the suggestions, I knew someone would know where to start :)

OS = Operating System. Mac, Windows, Unix, Other?

thanks @dpworkin… Windows, the answer to your question is Windows.

Is your CPU (the actual computer) inside anything? MIne did the same thing until I started opening the door to the desk it was in.

No, it’s not inside anything… nice try, thank you :)

“Windows, the answer to your question is Windows.”
Actually, that doesn’t mean much. You see, Windows XP is different from earlier versions of Windows, Vista is totally different from XP, and Windows 7 is kind of like Vista except that it doesn’t completely suck.

Regardless though, I have lived with up to five cats and cleaning the crud out of the heatsinks was about a monthly chore for me a little more often when spring came because Slagathor shed real bad and my normal cleaning would cool the PC off by at least ten degrees almost instantly. It’s always best to start with the simple stuff, and have a dust rhino clogging your CPU heatsink fins is easier to remedy than anything involving Windows.

I’m thinking heat as the culprit.

But maybe something like this could help.

Open System Properties via Start > Control Panel > Performance and Maintenance > System
[ System Properties may also be opened using the WinKey+Pause key combination ]
Select the Advanced tab and then click Settings in the Startup and Recovery section
In System Failure section, clear the checkbox next to Automatically Restart
Click OK and OK to exit

I know those are for Win XP. But it might be similar with Vista and 7.

Could be overheating. If it shuts down automatically while you’re working on something, that could be the problem. To prevent this, just keep the inside of the computer clean. Blow out the dust and if possible, get a more powerful fan.

Have you also checked for any viruses? It doesn’t hurt to do a daily virus sweep. Also, you should shut off your computer and give it a rest when not in use.

Did it shut down four days ago? It could be the latest Windows update. You might have your windows update settings set to the recommended automatic setting. It will supposedly restart your pc after it downloads and after you are sitting idle for a length of time but sometimes it does not.

Look at the calendar and see if the shut off occurs at the same time as the Windows updates. Microsoft sends out security updates on the second Tuesday of each month. They can also send out updates whenever they find a big problem. Most people don’t even know it is happening until they find their PC shut off on Wednesday morning. Look at the calendar and see if the shut off occurs at the same time as the Windows updates.
You can turn that off but then you leave yourself open to other problems.

I want my pc to just work and not be vulnerable to viruses or need updates. Windows 10 was my idea.

No one has suggested viruses. the Trojan completey took over and ran my old computer. it would shut it down, when it felt like it. i eliminated the problem with a visit to the woods and slug from my 40 cal. Glock.

Bought a new computer, installed two anti-virus programs and all is now lovely.

@john65pennington True, we did overlook the obvious. After dealing with computers for almost 30 years, I consider anti-virus software to be second to electricity when it comes to things that are essential for computing :P

Thanks to everyone for the suggestions, I really appreciate your help… I am using Windows XP… I’m using good anti-virus software which is up to date, have just done a scan to be sure but nothing was found… I am about to e-mail my favourite computer geek to ask for his opinion… he can do a remote tour around my computer and see if he finds anything suspicious…