OK let's start with the basics.
Turn on the headlights, yes or no?
Check the Cables at the Battery. I would suggest that you put a volt meter on the cable and find out what voltage is there when you try to start the car.
Turn on the headlights, yes or no?
Check the Cables at the Battery. I would suggest that you put a volt meter on the cable and find out what voltage is there when you try to start the car.