Question Old PC keeps switching off and then back on .

Jul 19, 2020
Hi, I was hoping the folk here may be able to help me please.

I have an old PC with an i5 650 3.2GHz, 4Gb ram, HD ATI 5750 1024mb card. PSU is a OCZ500sxs. Asus motherboard and running Windows 7.
The unit was overclocked when I bought it.

After using it for a while it will switch itself off and then restart after 5 seconds. Then repeat the process either immediately or after a short while. If left for a while turned off, it enables me to get some computer time before the problem occurs again.

The problem occurs when the room temperature is higher, always in the summer, never the winter. I downloaded the fanspeed program and the CPU is running at about 40C when idle and 40-55C when using multi browser windows or running a game (CnCnet). GPU doesn’t seem to move off 39C.

I’ve tried having a fiddle in the bios AI Tweeker section but frankly don’t know what I’m doing!

Any help would be greatly appreciated


Ps. My profile pic shows the bios screen
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Retired Mod
Sounds to me like it is a thermal problem, but not the kind of thermal problem you can monitor. I'd be willing to bet one of the capacitors, either on the motherboard, in the PSU or on the graphics card, but PROBABLY on the motherboard or in the power supply, is getting hot and triggering the the protection which is why it is shutting down. Given the very aged nature of the hardware, it could be any of those components or even something else like a failing drive.

I'd recommend you bench the unit with minimal hardware to see if you can get it to do it even when there is nothing installed on the motherboard except the CPU, memory and CPU cooler. That will tell us at least something about what it ISN'T, which should help to determine what it IS.

It's probably also a good idea to do a visual inspection of the motherboard and graphics card to look for any burnt spots, or any capacitors that are leaking or bulging.