Turn off your microwave and open the door. Notice the plastic lining on the inside of the door.
Insert the tip of your screwdriver in the seam where the lining meets the body of the door.
Work your way around the lining, prying it off as you go. Once the lining is removed, you will have access to the door latch assembly.
Check the screw holding the latch assembly in place. Tighten it if it is loose. If the latch is broken beyond repair, it will need to be replaced.
Remove the screw holding the latch in place and remove the latch.
Fit a new latch in the old one's place and replace the screw. If the door handle is loose, you can tighten the handle screws located on the inside of the door.
Replace the interior lining of the microwave door.