Odds are the motor has gone bad. The 01s were known for it. Mine did the same thing. I don't think you can get a motor from a parts store. The dealership ain't cheap. I happened to catch my local Ford dealer having a clearance of old parts and he had one motor left for the 2001. It cost me around $120 bucks or so best I can remember.
It's a straight forward replacement for the most part. I found instructions on line and probably those listed above will help too.
Good Luck!