There are a few things that will cause a pump to stop so here is a quick check list. Check power and ground as well as the pressure switch. If the motor is running, it might be a broken impeller shaft or the bearing seize may not be spinning the impeller to move water. It could also be plugged suction\\inlet piping or a faulty foot valve. Check the 'Prime' again. These are the main things that can cause a pump to stop operating correctly.