Frustrating failure

Right guys, i really need help here! 

It started some time ago when my Sabertooth P67 seemingly died on me. I simply shut down my computer, and when i tried to start it the day after, nothing happened. All i got was my fans spinning for half a second, then nothing. No beep code, no red LED's, no nothing.

I tried troubleshooting in many many ways and asking around on forums, and eventually figured it had to be my motherboard that had failed.

I sent it back to my retailer who declined return because the board was "Physically damaged". 

 

I though screw them then, and ordered a z77 sabertooth from another retailer and hoped this would be the solution. I just received it, placed it on a cardboard box, hooked everything up; 8 pin, 24pin, single RAM dimm, CPU and cooler, and when i went to short the power switch pins, guess what?

The fans spun for half a second then nothing. Only a single green LED at the bottom. Not even a beep code. I have also tried to reset the CMOS.

 

Anyone had similar experiences? It's frustrating the hell outta me...

 Shouldn't be a PSU issue. Have tried both the XFX and my old Chieftec.

It is extremely unlikely, but it could be the CPU died. Also try different ram.... and a different power supply. I would also call asus and explain you are having the same problem on a brand new z77 that hasnt been installed yet. Don't install the board in the case.. the screw scratches is what they use to determine if the board was used or etc.