However, just incase tomorrow or the day after it is not.. read on.
Here is a quick fix for a VERY simple problem that could cost you big in time and money if in haste, you turn to a plumber or even a new disposal. FYI... this post is assuming you are past the I dropped a spoon in there stage. :)
Case 1 - Disposal not grinding but you can hear motor running.
(there is something lodged in the blade. You are going to manually dislodge the food or item from the outside of the disposal) Here are a few pictures to walk you through.
Take the "Disposal Tool" (pictured on Orange towel- if you do not know where the one that came with your disposal is, use a larger sized alan wrench that fits in the hole at the bottom.)
As pictured in the second image (this is the undercarriage of your disposal) take your alan wrench or "Disposal Tool" and put it in the center hole of the dispsal.
Turn the wrench clock wise or counter clock wise to unlock the blade. This should not loosen the blade itself. You should even be able to hear/feel when the item that was lodged gets loose.
Run your water, and try the disposal again from the switch. It should work.
Case 2: You hear nothing. Try hitting the red reset button on the bottom of the disposal. This is pictured in the 2nd image. You may also try unplugging and plugging back in the disposal.
For all other problems, you might google "disposal troubleshooting" or "my garbage disposal doesn't work". These internet searches work for other problems as well. Remember, if someone built it, you can fix it. The only thing that might hold you back is finding out how.