PC restarts on shutdown

[MH_Wadester]

The last day something unusual has started happening to my computer.. when ever i click shutdown from the start menu or shut down the computer in any way it restarts basically immediately after. The only way i have found to shutdown my computer is by unplugging the power or turning of the switch on the power supply which works temporarily but when i replug or connect it back to power it boots or restarts. Now this happened a while ago to me when i had xp and supposedly got fixed when i installed windows 7. I have tried a few things to fix it such as:
- Turn of wakeup options for network adapter in the device manager.
- Turned of automatic restart on failure in system restore and power management.
- Tried a system restore to a previous date.
- Turned off any wakeup options in bios.

Its also weird because my computer was working completely fine until yesterday when it started happening and i havnt installed anything new in the last few days so i dont see why it would just start doing this randomly.

anyway any help would be much appreciated... its not a major problem but enough to bug and annoy me so i want to fix it without reinstalling windows 7 because i dont want to do that and would be a big pain considering all the stuff i have to reinstall and find.

[MH_Wadester]

any one got any solutions or help?

[K0ns3rv]

There is one thing that comes to mid but it's kind of a long shot. Someone might have tampered with your "shutdown" button making it call the restart procedure rather then shutdown.
Try running:

shutdown -s -t0

//K0nserv

[khakilang]

Or it could be hardware problem. Try changing the power supply unit in your computer. If the problem still occur than it could be your motherboard.

[edgaaa]

If you use windows vista or 7, try this one thing: start-->run-->cmd-->shutdown /p