Clear items out from under the sink so you have total access to the garbage disposal.
Check the electrical cord for the disposal to verify that it is plugged into the electrical socket all the way. Check the circuit breaker that supplies electricity to the disposal to ensure the breaker has not tripped. If the disposal is plugged in and has not tripped the breaker, but still doesn't work, move on to step 3.
Turn off the disposal using the wall switch. Locate the reset button on the bottom of the disposal and press it in and hold it for 15 to 20 seconds. Release the button and turn on the disposal using the wall switch. If the disposal still doesn't work, move on to the next step.
Use a disposal wrench to free the disposal if it is making a low hum but not turning. Turn off the disposal using the wall switch and locate the drive hub on the bottom of the disposal. Use the wrench to turn the hub clockwise. Turn on the disposal using the wall switch. Repeat the procedure several times until the disposal spins freely.
Replace the disposal if the problem can not be remedied with the previous steps.