HP Desktop won't power on. I was having trouble with the power button, thought I fixed it but now it won't turn on.

Year old (just out of warranty) HP Envy Desktop. The power button always gave me issues. It was hard to get it to turn on because the plastic cover didn't always connect to the circuit board button. I could feel the disconnect and it slowly got worse. It finally stopped working. I opened it up, took apart the button/top USB buss area, and resolved the button issue. It presses perfectly, every time.

Reassembled the computer, and now there's no power. I hear the load "zap" when I plug the cord into the power supply but nothing else happens when I press the power button.

So, could it be the power supply?

Is there a way to jumper the switch leads on the motherboard in case the switch is broken? The labeled "Switch" cable plugs into the board with two wires.

Thanks