Hi,

My PC's started switching itself off occasionally during startup. I don't know what's causing it. I haven't done anything to it lately that I can think would be a problem. If I try to switch it on again afterwards it won't work unless I switch it off at the plug and wait a few seconds. Then I can switch it back on again and it'll start up.

Does anyone have any suggestions as to how I can stop this from happening?

Thanks,
Joe

Try first to open the case and clean out all the dust. See if your CPU fan is working, as well as a chassis fan. Heat is one of the biggest culprits in unintended shutdowns.


DR

rigacci is absolutely right about heat and cleaning out you case, but pay particular attention to the CPU heat sink and fan assembly as this is the critical area. You should also check out the areas where air is drawn into the case. Even if this isn't causing your problem it is something that you should do occasionally, the frequency will depend on the dust level around the computer. Before you touch anything inside of the case touch the metal of the case to discharge any static build up as this can damage board components.

If you leave the computer off for five or ten minutes and try to restart it does it work, or do you still have to unplug it from the receptacle and plug it back in to make it work. If it is the latter then you could have a bad power supply. If you have a spare PSU you could try switching it and see if the problem persists.

There is a way to test the PSU with a Voltmeter, but you need some basic tech skills to do this, if you are up for trying it let me know and I'll tell you how to bypass the motherboard and test the PSU.

Thanks for the advice. I'll try giving everything a clean, although I did do it a few months ago and it seems odd if it's a heat problem that it would only happen during startup when the computer's still cold. I would have though it would be more likely to switch off after it's been on for a while which never happens.

Testing the PSU sounds like a good idea. I'd appreciate instructions on how to do that.

Thanks again,
Joe

It may seem counter intuitive to have the heat problem when you first start the computer, but it can only take seconds for the CPU to reach temperatures that are unsafe for it.

Testing the PSU. If your PSU has a on/off switch on the rear turn it off, if there is no switch unplug it from the receptacle. Remove the 20/24 pin connector from the motherboard and place a jumper from the green wire socket to any black wire socket, turn the power back on. To read the different voltages you will need to know the color codes for the different rail voltages, you can see them here.