No Power - yet another post

I have no power to the motherboard.
I have verified power to the Power Supply.
I have replaced the Power Supply with a new one.
I have 5V on the PSU MB Purple Wire. I have 5V on the PSU MB Green
Wire. No voltage on any other wires. I thought that Green voltage
should go below 2.4V when switch depressed but no change occurs.
I have continuity across the switch when depressed. I pulled the switch
pins and shorted but still no power up.
I see no burnt out capacitors.
I tried to power up by removing all power leads to HD,FD,CD, DVD. No
Luck
CPU fan turns freely.
Case fan turns freely.
It is a P4 system but I dont see any model on the acesss side of the MB
other than Made in China!
Is the MB Bad? How can I further test it?

Thanks
Steve