It has a 24pin and a 4 pin and they are both connected. I know it isnt the psu or case buttons as I have used both of these on another mobo as a test. The whole case underneath is just metal too and its touching that. Also the switch is on, on the back . The thing is I'm builing two computers at once here, identical motherboard and case, both have this problem. Also I don't want it to wreck my 8800GTS if it is shorting out. I might just phone up scan to get it replaced with another model.
The back of the motherboard shouldn't be touching the metal motherboard tray. That's why it won't work.