My girlfriend's 2000 Regal currently has zero functioning windows. Im able to remove the plug from the master switch and via a jumper from a 12v positive get three of them to go up and down. The switch is brand new. I've tested the terminals on that plug and there is indeed a positive feed (yellow wire) coming into the plug when the key is on.

Also there only seems to be a circuit breaker inside the cabin related to the power windows and does not seem to be any relays involved?

I'm currently stumped. Anybody have any ideas?