Originally Posted by Jay H

Sounds like to me your broke the freewheel assembly in the rear hub. You should be able to freewheel (spin the cranks "backwards") but obviously you shouldn't be able to spin the pedals "forwards" without the rear wheel moving. Inside the rear hub, there would have to be pins (for lack of a technical term) that catches on the gears when you pedal forward which perhaps have broken off so now you can freewheel in both directions.