All of the above is true. Perhaps manually set all the digits of the score reels to "0". Score reels are big culprits of NOT resetting a game.
You WILL have to clean all of them eventually, but maybe this might help you stop the score motor. Cleaning stuck items is going to be necessary.
You also might unplug the Playfield using the Jones Plugs. This might assist you to see what is causing the motor to stay spinning.