try the switch first whether it be a spare one you have or a new one doesn't matter as long as it's a working one. if that doesn't help then chances are good that its the motor.
Okay well check your fuse if its good
Pull off the interior door panel check if it switch is connected properly if not it go to the
Wreckers and get a switch I doubt it is the motor
the Glass could be off track,but I would just take the door panel off and check for any visible damage, torn wires, motor smells smokey,broken mechanical parts etc...
I had a problem with my window seal and it was causing it to knock the window off the track. when the window glass is off the track it cause excess stress on the motor and could have burned out the motor....