Power issue with MAC G5

Hello TehyV,
I have problems powering up my MAC G5. I ensured to check the cord continuity and the power from the wall. They were both good. However, when I turn on the button at the front of the box it does not work. Is it that the problem is a fried power supply of the switch? Can someone help me troubleshoot using a multimeter.
Thanks for your help.
