h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Some computer advice, if you would. For months now, my computer has occasionally been cutting out and restarting, usually not long after start-up. When it is restarting, a message says "Power supply surges detected during the previous power on", and mentions an "unstable power supply unit". I have tried looking through the startup settings, and there is no obvious on/off tool that would be doing this.
Does this mean I need a new power supply unit? No other systems appear to be harmed, except for my annoyance at having to wait for the computer to boot up again. I have a bit of Christmas money left, so I can probably afford to replace one component, but only one.

Disclaimer: I am not a computer knower, at all. Just a thought.

Power supply units are not that expensive, so replacing it sounds doable. It's probably a DIY, too. Youtube tutorials should exist. However... such error messages need not necessarily be caused by faulty hardware, but by faulty software, instead. If you don't feel intimidated by the prospect, try re-installing the operating system (Windows and Linux aren't difficult to re-install, I don't know about Apple stuff...)

Have you given the power supply fan a clean?

Have you got a surge protector between your power lead and the wall? Many power strips (the ones with four sockets) have a built in surge protector. If your electricity supply is dodgy rather than your power supply unit, then a surge protector might solve the problem.

But it seems more likely that you need a new power supply. How handy are you? Can you unplug things, and unscrew things? You would have to examine the existing power supply, check how many different connectors it provides, then order one that has the same (or more) connectors coming out of it. You'll also have to check the dimensions and make sure that the new one fits.

I'd agree on adding a surge protector first; it may be that some other piece of electrical equipment is generating lumpy mains spikes and causing the problem - in order that could be central heating, a fridge or a fluorescent light.

I had a PSU fail on one of my sons' machines last year, but it had the presence of mind to release the magic smoke, so we knew where the problem was. Somewhere along the line between failure and repair the power protection component on his hard drive got damaged, so I had to get a soldering iron out to recover the data.

After surge protection the next likely issue is a failing capacitor in the power supply system somewhere. This could be in the PSU or it could be on the motherboard.

Cool old Guy soldering radio interference surpression coils
"Guess we can keep it to the level 'exchange power supply' with an identical type and model as best advise.

Last I had was a coil broken loose, the tin was crumbled, only to find out after watching the supply in the dark. (the boing has a coil attached and the disco can be the spark)"