My vehicle cranks sometimes and sometimes it doesn't and it has a good battery

My 2004 Pontiac Sunfire is not turning over and the battery is good. I would like to know what could keep my car from starting properly, and what could cause all of the lights such as the check engine, gage light, theft light, etc... to remain on as well? Another question I have is my brake lights, hazard lights, and blinkers are not working. I tried the WD40 trick, but no luck...could all of these issues I am experiencing be tied into the same thing?