Originally Posted by
bikeman715
sound like you need a new freewheel. (the gears on the back wheel ).Take the bike to your LBS and have them switch it out for a new one, part (the new freewheel ) / and labor should be no more $25.
The OP said the
chain doesn't move. If that's a correct description, the problem is in the crank, either a dead FF crank, or a failed swage on a 2 piece crank.
To the OP, if the chain turns with the pedals, but the bike doesn't move, then bikeman is right and the freewheel in the back needs replacing