If you cannot rotate the impeller by hand (finger) the bearings have frozen due to rust due to a badly leaking shaft seal. Shaft seal leakage is very evident at the front of the motor. If by some chance, you do get the motor to move, you will regret the terrible sound bad bearings make right up to the point the motor burns because the drag on the bearings will cause it to draw more amperage that it is designed to handle. Burn is literal. Can also damage wiring to the pump.