Computer turns itself back on
 

Recently my PC has decided to turn itself back on straight after I shut it down, as if shut down counts as restart. I've looked in the BIOS, power options etc, and see no reason for it doing this.

Any ideas?

Your computer loves you just that much.

Maybe your PC heat up.

Does it turn back on if you perform a hard shut-down? (Pressing the power button while the computer is on until it immediately shuts down) Or does this only happen when you shut down via the operating system commands?

Yes it reboots that way too.

Did you build the computer yourself?
If so, feel free to give us a make and model for your motherboard and possibly even your computer case.
If not, what POS retail computer do you have?

I've had the computer years after I built it myself. It started doing in the last month or so.
The motherboard is an Asus A7N8X (yes I know, getting on a bit)

Check this to see if it helps solve your problem.
Windows XP Shutdown Troubleshooter

EDIT: Post here with your findings.

I have had this happen before.

For me, the computer got fried by a thunderstorm. It was off (I can't remember if it was initially on or not), and then I went to turn it on. Nothing. I pressed the button several times and finaly it came on and booted into Windows.

I then shut it down and presto, it rebooted. THis happened a few times but did eventually stop. The source was the motherboard.

It's still doing it guys. I can't imagine how much power it's using being left on all this time, and turning it off at the back resets all the BIOS info and it's frustrating changing it all every time. That, and it probably dosn't do the PC any good.

I've disabled that 'reset on error' whatever option in 'system and recovery', nothing changes. Disabled Wake on Lan and disconnected USB devices but no changes. Remember this happens when I hold down the power button to boot off too.

This is a stretch but, have you changed the CMOS battery? When you said that when you turned the machine off in the back, it reset all bios settings.. that sounds like the battery is dead.

Havn't changed it no. I think the reason it resets itself is that when I want to turn it off, I use the shut down option, then it resets and before it gets to the BIOS during boot up thats when I turn off at the back.

Either way, I'd still try replacing the battery. You did say it had been quite awhile since you built the machine.

How would I go about doing that?

If you open up your case you should see:

http://img204.imageshack.us/img204/8423/a7n8xbo0.jpg

Circled in RED is your battery. take it with you to any store that sells batteries, and get the same exact kind.

A big bump to tell you guys I have finally sorted this. It was the power supply all along.