Power Button not working on my Cabinet Plz Help

[anand1]

My cabinet power Button is not working. When i start my PC it autonatically starts up without having to press the Power Button. And during ShutDown also the Power Light do not goes off and i have to manually switch off the UPS.

After having such problem i opened my cabinet and tried to manually short the Power Button pins given on the motherboard but it also doesn't worked. It seems that the motherboard is not enabling the Power Pins to be shorted for startup.

The Reset switch is working good but having the problem only with power button. The problem started when i replaced ny SMPS after cleaning the Cabinet and according to my knowledge i have Assembled all my PC correctly.
Plz Help....................!