Motherboard blew up for no reason!

I recently got a CoolerMaster Extreme Power Duo 650W power supply for my new PC I am building. The motherboard I was using is an Asus P5ND2-SLI and the processor is an Intel Pentium 4 Processor 650, 3.4GHz. I only installed the PSU and the processor so I could first test if the computer can first power up before I added the rest of the components.

After plugging everything in, including the pins for the panel in the correct places; I put the PSU power lead into a surge protector socket and as soon as I switched the on button from the back of the PSU, the motherboard started smoking! I asked my friend about this and he reckons I may have misplaced a pin on the panel but I assure that I placed the pins correctly and according the motherboard's manual.

I now have no idea why the motherboard blew up, anyone know what could have caused this?

can i see a pic of this mb? thanksticktocktick201

Here you go.

And may have been defective, shame I can't get a refund as I had that motherboard unused for 2 years! Looks like I have to buy and new & better model now.

Thanks guys