Engine won’t start, battery is full and radio and lights etc are working

Check engine light is on while start the engine

Havent used my car for months as I was given a work car, just went to start it and nothing happens at all. Plugged the battery charger in and out says the battery is full but it still won't start. Wha… 

Piston Slap engine could fail at any time

Slap shift not working at all an if I go over 25/30 it won’t shift drive nor the slap shift

Sounds like engine piston slap