If you still have the panel off, try taping the motor with a hammer or wrench while pushing the switch, also you can try disconnecting the power wires from the motor and giving the motor an 18V jolt from a drill battery. it wont harm the motor in the least bit. it just helps break free the possible rust or corrosion that the motor has collected over time, if neither of those theories work, you might need a motor.
As for the rear windows, Im guessing you have allready checked and possibly replaced the fuses, if the fuses & motor are good, (repeat above mentioned to check motors) but your switch wont roll it down, try to find a good donor switch and try that, if that doesnt work then you have a bad connection somewhere or a broken wire in one of the looms, best place to start is where they are subject to moving. ( in the door jams).
hope this helps you.

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