System won't shutdown after pressing shutdown in windows.. only from power button or psu!!! tried everything!!

[Darren James]

As you can read from the title after pressing shutdown in windows the system stays on and just reboots in to windows it doesn't shut down unless the power button is pressed. I have removed everything connected to the motherboard.. tried test psu's, clearing the cmos, removing the cmos battery, i have change power management settings in the bios so that all power-wake "like" settings are disabled but nothing.. i have gone into windows and done a clean boot using msconfig, I've updated the graphics drivers (someone suggested this in a forum) I've sfc /scannow in cmd line no errors. I have tried changing the value from 1 to 0 and 0 to 1 in the poweraftershutdown location in the registry, I also went into system advanced properties and unticked automatic restart on startup errors or something along that line.
I was going to update the bios but it only lets me from a floppy and i don't have a floppy drive.. the only good thing i managed to accomplish is to boot to safe mode and it will shut down using windows so this must mean its a software error right? Some programme is still running but i don't understand why a clean boot wouldn't of stopped this??

It then wouldn't shutdown using safe mode with networking so I went back to normal mode and disabled the network drivers and unplugged the ethernet but na! no luck! Can anyone please help me solve this issue

I have a ga-n650-sli4 with a q6600

 

[Bossyfins]

Is your windows all updated?