Hello all, i'll be short cause no time XD

I have a m2-atx connected with a old p3 mobo (800mhz celeron on it)
the power supply should automaticcally send the off signal to the mobo when i cut out the ignition but nothing happens....
Also when i manually turn off pc by START close session the pc correctly turns off but after some seconds it comes back on again even with ignition cutted off

any ideas ?

thanks in advance