Random startup and shutdowns

My Xp machine recently has a problem where it starts up in the middle of the night and does a normal shutdown (not cutting the power like when it over heats) and reboots about 5 times during the night. It would stay up for about 15 to 30 mins then shut down and restart a few seconds later. The computer isn't connected through the ethernet but does have a usb wifi adapter. Once, I noticed the light on the wifi as well as the keyboard was still on even tho the rest of the computer was off, then the whole computer turned on. Has anyone heard of a situation like this or have any idea what could be the problem?

Seems like a hardware problem but could a hardware problem cause the computer to shutdown normally? or could a software issue cause the computer to turn on automatically? The computer wasn't on sleep or hibernate.

 

It's possesed Needs a good exorcism

Seriously maybe you were fiddling with the task scheduler and by accident in the setings of 'create task' you set the notebook to keep restarting a few times trying to complete a certain task.

Oooor it is your evil neighbour taking command of your computer through the wi-fi connection

 

You might have it wake on USB or wake from LAN/Network.

Go to your Bios and disable it.

 

As far as i can tell, every power on option has been disabled and there aren't any scheduled tasks. I'm not even aware of any task that can turn the computer on from a powered off state.

 

Check the BIOS settings.

If power is available, either from the wall or a battery, the BIOS is still able to wake the computer and start the O/S appropriately. Win7's task scheduler can update BIOS settings to make this happen. Also, both ethernet and wireless network activity can cause a power-up if their "Wake on Lan" settings are enabled in the BIOS.

 

I changed the MB and reformatted to XP, checked all power options. Only thing enabled under power management was acpi and it still turned on by itself. Then switched psu and same result. This is getting a little freaky. Only thing I can think of is maybe damaged surge protector but thats a little out there. If task scheduler can tell bios to turn on the machine, could a virus in the mbr do the same?

 

Of course, an appropriately written virus could do anything. You might consider using one of the anti-virus scanners which boot and run from CD. Malwarebytes has a good reputation. There are others.

Don't forget to check all the wiring to make sure there's nothing worn, shorting out and making an intermittent connection -- like maybe the cable to the power switch.