Xserve G5 no power

The server has been running successfully since the beginning, but after a power went out in the building, multi times in a night, even with it plugged into an UPS, it now won't boot up. I have unpluged, waited, plugged back to the UPS and to a good wall socket and cannot get anythjng. I push power button, no noise, no lights.

Could the power supply have been damaged by the power outage?

Thanks for the reply, it's an email server. James