Unplug the Frigidaire microwave's power cord from the wall outlet.
Use the screwdriver to remove the screws in the back panel and the cabinet sides. Take off the back panenl and lift the cover off the microwave. The capacitor is located in the back of the microwave and is shaped like a cylinder-style battery with two terminals on the top.
Pull off the two wires from the capacitor terminals, one at a time.
Touch the tip of a screwdriver to one of the capacitor terminals while holding the screwdriver's insulated handle. Wear work gloves while doing this. Slide the screwdriver blade against the first terminal until the tip of the tool also touches the second terminal. The capacitor makes a popping sound to indicate the power has been discharged.
Remove the stirrer belt from the top of the appliance. Stretch gently to remove the old belt. If it is broken, simply slide it off the two grooved wheels.
Stretch the new belt over the two grooved wheels.
Slide the clips on the two wires back onto the capacitor terminals.
Put the cabinet cover over the oven and secure it with screws on the sides.
Fasten the back panel to the rear of the microwave with the screws.
Plug in the power cord.