Ok I tried another powersupply but same problem.

I also have another motherboard that is exactly the same. I plug in the CPU, plug in the fan+heatsink, and everything else and it works fine. So I believe I have a faulty motherboard.

btw: on these new ASUS motherboard, some of them will not work unless you have a heatsink and fan on them, at least thats what happened with me. One more thing. If your ever wanting to check your CPU temperature to see if it is to hot heres a little website that has a general guide to CPU temps on it. You will have to convert to Farenheit though. http://www.heatsink-guide.com/maxtemp.htm