If you are experiencing a problem with your disposal, there are a few things you can do before calling for repair. First of all check and see if the power has tripped. There is a reset button on the underside, should be located under the sink. By resetting allot of times this take care of the problem. Both your dishwasher and garbage disposal share a connection, so if you are having problems with the plumbing related to the disposal, it is probably going to also affect your dishwasher as well.
Sometimes the blades will become jammed, often taking a large stick, like a broom handle can dislodge the blades. Another thing is there is something stuck in the disposal. Once you make sure power is turned off, you can stick your hand inside the drain and see if a spoon or something else is stuck in there.