You will have to give a Model Number

Here is your parts breakdown
Model MDG6657BWW

Here is a service manual of similar models, to give you an idea of what is involved.
http://www.servicematters.com/m...ibrary/docs/16023110.pdf

Not a hard job, hardest part is usually getting the damn clips that hold the motor off and back on. Does require some mechanical ability but if you take it slow, be careful not to break anything and mark any wires you disconnect, it is definitely doable.

You just have to decide if it is worth investing $100.00 into the unit.
So make sure the motor is not turning before going any further.
Who knows could be your belt snapped or came off the motor pulley.
Normally if it is the motor if left on it will trip it's internal thermal cutout because it overheats.