Can you hear the motor running at all? If not then I would think that it has gone out, or lost power to it.
Unfortunmatly unless you are skilled at diagnsing these machines there are just too many possibilities to go over for me to be able to walk you through each of the tests.
If you could give me the model name I may be able to locate a service manual for the unit and that will have complete diagnostics proceedures in it. I will look under the model number but the sitre I get these from uses the model name rather than the model number most times.
Awaiting your reply; THS
Does this look like your unit?