You are right! It`s pwr_sw on front

You are right! It`s pwr_sw on front panel not PS_ON on ATX connector who have 0.8V.
Mobo is not starting by pressing pwr_sw on front panel (the reason is obvious-0.8V on it).When I try to force it to start by shorting "green&black" wire on ATX connector with supply present nothing hapend.MOBO is dead!
The main problem is with +5 on USB-s who have shortcut to null.