don't start, battery good, it was running great, no lights on on 2003 BMW 325xi

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
it was running great . all of a sudden didnt start, battery is good and no dashboard lights on
(2) Answers
If is cranking over then have to start with basics and see what is missing when turning engine over---spark or fuel and go from there.