Shutdown not quite finishing the job

mrpleasant · 25 Nov 2009 at 22:26

My self-build PC is nearly two years old and has been working fine until very recently. In the past month or so however it has begun failing to fully shutdown around four times out of five, leaving both case and CPU fans running though seemingly without any hard drive activity. The power button on the front won't start it up again. I have to switch power off to the unit completely, either by the wall switch or by the PSU switch on the back of the case. I wait until the sound of the fans has stopped completely, then I turn the power back on and the front power switch will then work. Interestingly, if I put the PC in sleep mode, the fans do stop. All is completely silent and only the slow flash of the LED on the front of the case lets me know it's asleep rather than powered down. It's more or less consistent doing this, but last weekend I moved the whole thing to the kitchen table to take a proper look and lo and behold it worked flawlessly. Recently upgraded to Windows 7, by the way, but can't recall if this issue ever occurred prior to that. Any ideas gratefully received.

PS If I'd done any BIOS upgrades or major hardware changes recently, I would mention it. I haven't.

ETNiES · 26 Nov 2009 at 01:51

Try changing the socket its plugged into.. If it worked in the kitchen it has to be the plug or extension, if it's plugged into an extension try plugging it directly into the wall.

Did the problem start happening again when you moved it back?

mrpleasant · 26 Nov 2009 at 06:26

Thanks, I'll give that a go. If anyone can explain why this might help I'd be interested to know. There are other devices plugged into the same gang socket and therefore getting their power from the same mains socket, all with no apparent problems. When it all worked in the kitchen I put it down to ensuring good connections on the motherboard. Maybe it was just a coincidence, but I powered it up and down several times and it worked perfectly.

ETNiES · 26 Nov 2009 at 14:16

It could have just been the connections your right, thats why I asked if it started happening again when your brought it make to its original location, if it didn't then you know it was just a connection issue.

ran_out · 26 Nov 2009 at 15:42

It could be your power supply starting to go, I can't give you anything to back that up. But a similar thing started happenning a while back with mine and a few days later woke up to a burning/chemical smell and the PSU had died in the night (whilst the computer was powered off!). But I also used to get this problem when pushing my overclock a bit further than usual after shutting down, although this hasn't happened since i replaced the PSU.

mrpleasant · 27 Nov 2009 at 19:24

Thanks for the replies. One new 'feature' I've noticed is that after the software shutdown that doesn't quite finish, I can force a complete shutdown by pressing and holding the front power switch - as you would if the machine had frozen completely in mid-use. A couple of seconds of that and the fans finally stop. Probably not very useful info, but thought I'd mention it anyway.

If it's the power supply I suppose all I can do is wait for it to go completely or exhibit clear signs that it's on the way out. At the moment I can't be sure what the heck it is. Weird that putting it in sleep mode works perfectly though - ?