Computer won't start

[satria]

I recently assembled a celeron 300a system w/ soyo sy6ba+ MB and ATX P/S. After assembling other components and turning it on, nada. No fan, no power. To troubleshoot, I've:
Changed P/S and case.
Verified connection from P/S to M/B several times.
Verified connection from M/B to case.
Verified that there are appropriate voltages coming out of P/S.
Verified that the P/S is the new type (20-pin).
Set it up w/ nothing but M/B & CPU.

[GVolosky]

Defective Motherboard - P/S should start by shorting "Power" pins on mobo without anything else on board.......