Car won't start

Low voltage, loss of electrical grounds, BCM failures, do the simple stuff first like voltage drops and circuit testing before diving into computer problems. Make sure you have a preset saver tool plugged into the OBD 2 port and energized before disconnecting main power, an error like that can cost you at least a hundred bucks at the dealer to get the onboard systems reflashed.

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