PC turns on when plugged in!

[RegEdit]

HP Media Center m260n.
Why is it that a computer turns on and boots to the desktop as soon as I plug in the power cord? I'll have this thing turned off all night, then plug the power cord back in and it starts up without even pushing in the power start button. Bizarre.

 

[Paul Rodgers]

Did you check the BIOS?

 

[iisjman07]

Yup that's a BIOS setting. I can't really see the need in home desktops but on servers this could be very useful

 

[RegEdit]

I think the motherboard is going on this PC. Got a IRQL not less or equal blue screen in trying to boot up. PC Check 6.5 said that the disk failed the stress test. Fine. I swapped in a new drive and have been trying to boot to some Windows CD's. It keeps saying no boot device found. Sometimes the "no boot device" text will flash again and again several times on its own. The CD and DVD trays spin first too (I've tried Windows CD's and Windows DVD's) -- same thing. For a while I also got a message saying that the CPU fan was not working (and the computer is in need of servicing) even though it WAS working fine. PC Check 6.5 indicated that the CPU and MB were all fine, which I think is a false positive regarding one of the two.

Also the BIOS freezes up! The CMOS battery is + 3.17

ASUS P450-LA motherboard

 

[AdamsAPlus]

I have seen this when there was a short. So If it's not the BIOS check the wires from the Power Button to the Mobo and also check the PINS for the power button on the mobo.

In my case the person didn't have the post that keep the mobo away from the case. the mobo would touch the case and boot up. I was shocked he didn't mess up the entire mobo.

 

[parker.casey]

I'd also check to make sure that the power button is connected in the first place, and that the "Clear CMOS" jumper isn't shorted.

 

[RegEdit]

See post 5. Motherboard failure.