Look inside the sink cabinet at the bottom of the disposal. Look for a hole in the center that fits the Allen wrench.
Insert the wrench and spin the InSinkErator with it until the disposal can move freely. Check the red reset button on the bottom of the disposal to ensure it is depressed.
Turn the faucet on cold and turn on the InSinkErator. If it runs but it sounds like something is jumping around in it, remove the jammed item with a pair of tongs.
Remove whatever foodstuffs or foreign object is in the disposal with tongs. Do not use your hand.
Check your fuse or breaker panel to ensure that a fuse wasn't blown or a breaker tripped.
Press the small red reset button on the bottom of the InSinkErator, inside the sink cabinet. It should sit flush with the bottom of the disposal when reset.