Noidea

A new PSU seems to have sorted the problem. Thanks for your help.

Thanks Plastic Nev, I have just tested the power switch and wiring and they are fine. I have realised that there is an LED lit up green on the board whenever the mains is connected. It seems odd to me that repeatedly turning the mains supply into the PSU off and on somehow gives it a kick-start, but it is a trick that works consistently. I have ordered a new PSU, so I'll find out soon where the issue lies and report back. Thanks again.

Hello, First post, so please be gentle. I have a self-built PC that has developed a problem over the past 2 months: Increasingly often, pressing the power button to start the PC does nothing. No lights, no noise, nothing. What I found is that by switching the power off and on again at the mains a couple of times, the PC will switch on. I've now got quite used to doing this, but it makes me think that something is going to fail soon and should be replaced before it does. I would like your opinions on whether it is more likely to be the PSU or the motherboard that is at fault, please. I don't know whether it is relevant, but the PC otherwise works fine except for occasional temporary freezes, that last for maybe 30 seconds and then resolve themselves. My motherboard is an Asus M4A785D-M Pro and my PSU is a Seasonic X-400FL. I use the onboard graphics and have a low-power chip, so believe that the PSU is big enough. Thanks