Pi 3 Will no longer power on

[fraggle]

"When I connect both wires to any of the various test pads intended for power and ground I get 0.2 volts."

How do you mean any of the various test pads? To be clear you should only connect 5v to PP1 OR PP2, and you should connect Ground to PP3 OR any solder pads at the corners of any of the port shields.

Can I ask what is the voltage on the GPIO header?

1) Probe pin2 AND any of the metal shells of connectors (usb, hdmi, etc) which are all grounded - what do you see?
2) Probe pin4 AND any of the metal shells of connectors what do you see?