Power off your microwave and unplug it.
Open the microwave door and insert the tip of your putty knife under the border of the rubber inner-door trim. The trim is held in place with clips.
Pry the trim from the clips to remove it. This will also expose the inner-door screws.
Remove all the inner-door screws with your screwdriver.
Remove the screws on the top and bottom outside door hinges.
Remove the microwave door from its hinges and off the microwave.