i recently bought a new rig but it wont work?

items =

- Intel Core 2 DUO E6400 "LGA775 Allendale" 2.13GHz (1066FS -
Retail
Corsair 2GB DDR2 XMS2-6400C5 TwinX (2x1G
Gigabyte GA_965P_DS3 (Socket 775) PCI-Express DDR2 Motherboard
Hiper 580WATT PSU
case and HDD

i connected everything made sure everything is connected to the right place but when i turn on the computer nothing boots up. The BIOS screen doesnt even appear, it just says "No signal". I thought it was the PSU because it started rebooting itself a about 10 seconds after the "no signal" screen had appeared, so i tested it with my other 500WATT PSU but the same thing happened. The computer didnt boot up/
I know the it's probably not the RAM coz i checked that it was connected properly and the CPU i dont know about, but i'm certian that i put the CPU in properly. It's probs not the HDD because the computer would still boot up and say "no hard disk was found" or some shit.
I have no idea what is wrong and the only conclusion i can come to is that the motherboard is faulty.

Any suggestions on how to fix it?