On something like this you will need a wiring diagram & a meter to find the root cause of the failure. I am providing you with a wiring diagram that has the path of voltage to the motor outlined. Everything in the path has to read closed continuity on the ohmmeter. I suspect the belt switch or a wiring harness problem.
to the dryer before attempting access.
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:
Sears Home Services
SAFETY NOTICE: Be sure to disconnect power to the appliance before performing any repairs. If you are not comfortable with doing any voltage checks that might be recommended, please contact your local service provider for repairs. Be aware that there could be sharp edges inside the appliance that could cause cuts or other injuries to yourself or others.