If the washer has stopped spinning then you need to remove the back panel and from there check the belt is still on the pulley on the back.
If thats fine then at the bottom you will see the motor. Check the wires going to this on the side are fine. If the are then you need to remove the motor and at the back either side are the carbon brushes. Take them out and see if they have worn down. If so then you need to replace them and that should get the washer spinning again.
But if they are fine as is the belt and the water is drainign away fine then its either the motor itself or the control board which both are very very expensive and usually not even worth fixing as Whirlpool parts are expensive.
But check the belt and the carbon brushes in there and see what you find and let me know.