My serpentine belt is not spinning. I'm thinking it is either the idle pulley or the AC compressor pulley.
It is likely that one of your ribbed or slotted pulleys has seized up causing your belt to be unable to spin. It is also possible that there may be a problem with the crankshaft drive pulley. It is possible that the seized pulley could have caused damage to the pulley or the crankshaft alignment key which may have caused the pulley to break. If this happens, the crank pulley will not be able to drive the pulley any longer. I would ask for help from one of the mechanics at YourMechanic determine if the serpentine belt needs replacement.