Car won't start

My car has done the same stuff like lights flashing at night and no key in the ignition system n then it burnt out my head lights then a month ago I was driving it about one hour n the air conditioning system stopped running cold just hot air n went to look at it n fix it n then my car wont start and the green key light on my dash keeps flashing said it's the immobilize system to show that antitheft key symbol idk what to do or why this has happened