I need direction on a locked engine on a Craftsman 20hp riding mower ?

I was mowing with my Craftsman 20hp riding mower when it suddenly died. It had no power so I knew it was electrical. I finally found the fuse and replaced it. The lights now work, etc, but the engine must be locked up. I thought at first it may the solenoid but when I replaced it the motor still just "clicks" when the key is turned. It has plenty of oil and I have always checked the oil before using the mower. It is a 2000 or so model. Any suggestions will be appreciated. I removed the plugs and sprayed WD-40 in there thinking maybe that would free it up.