New build: no POST, PSU pin confusion

[mosherben]

Need some help. I've got a AMD Athlon II 240 CPU and a ASUS micro ATX motherboard, the M4A7BLT-LE Rev 1.016. I've got a Corsair VX 550W PSU which has confused me. The board has 24 pin power connector, and the PSU has a 20 + 4 power cable, but I don't think it fits properly. I've tried turning it on and I'm not getting a POST. If it helps then the fan turns on for 2 secs and then stops.

Any ideas?

[mosherben]

Right, finally read the manual again and fixed my PSU confusion. The PSU came with the 20 + 4 power cable detached

Onto a serious note, still no POST! I've got 1 stick of corsair DDR3 1333MHz RAM installed, no hard drives or dvd writer setup. My 4 pin ATX connector was 8 pin, which was again, detachable.

What measures to take to try and get the build to POST?

[mosherben]

UPDATE:
It's posted No idea why it wasn't before, maybe a short somewhere. I started with clearing the CMOS chip using the jumper on the board. It posted using the onboard graphics and one stick of ram, and so I moved forward with 2 sticks and the GPU.

I eventually worked out that the hard drive seems to be faulty. It won't post or get the fans running when it was attached. I tried putting the hard into this computer, and when I turned it on there was smoke coming out of two chips just above the SATA power socket on the hard drive.

RMA time I think, I thought the drive had cost my old system when it wouldn't boot up after the smoke but guess it needed 5 mins to recover.