Motherboard cannot turn on, but..

Hello mate..

i have a motherboard with rather weird condition.

The motherboard is HP Irvine GL6E, LGA 775/Socket T, Intel (MCP73S01) Motherboard.
Single chipset nvdia for lga775.

If i turn to power switch or short with metal from the ps-on front panel, the fan just twitch..
Seems mosfet shorted..
So, i check with multimeter all the mosfet, including vrm, memory section, etc.
But every mosfet that i checked seems normal...

With confuse, i try to jumper green-black cable through the 24 pin socket in motherboard.
The motherboard now turn-on, and the funny thing is, it's now beep.
A single beep that sign the system is ready..
So i connect it to the monitor and it has display.

Trying to install windows, everything is running.

But, if pull out the jumper, the motherboard shutdown.
And if i try to turn on through front panel, fan just twitch again..

So, what's is the problem, and where i have to start to check..?

Thanks a lot.