Need help......Again

I seem to be on this streak right now where I can't even build a computer without running into problems. Heres my problem

Brand new computer

ASUS A7S333 motherboard Socket A
AMD Athlon XP 2200
300 Watt allied powersupply.
WD HD
MSI CD-RW

Ok I connect all of my switches to the motherboard plug in a power cord to the back of the PC, press the power switch, and the CPU and Case fan starts to turn but then they both stop, and of course the computer doesn't run. I've triple checked all of my wires, and connections, and re read the manual but it all seems fine. I turn the power on again, both fans start to turn for 1 second then stop.

Any ideas on what the problem might be.

I'll ask a potentially stupid question, but do you have arctic silver or some other heat transfer compound between them? I've had a system shut itself down before because I didn't cover the entire surface of the chip with the heat transfer compound and one corner overheated.

If you have a spare power supply you can put your hands on, it would probably be worth your time to test the rest of your system with a different power supply.

The only type of thermal grease I have is the stuff that came with the heatsink. I put the grease on all contact points on the CPU.

I'll try a different powersupply tomorrow.

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