either the drum has jammed, or the belt has worn, other thean that the motor meeds replacing, if so contact manufacture direct, usually cheaper, but if it does need replacing if you include labour, probably worth buying new.
simon
December 2007
I had similar problem which was caused by a faulty relay. The primary circuit worked fine and strangely enough the relay worked, but only for about 20 seconds so no sooner had the drum started to turn it stopped again. After a minute or so cooling off the same performance was repeated. There's no reason why you can't remove it and apply bench test to prove its faulty.