Have you tested the battery to see if it has power in it?
If it has have you made sure the contacts are good?
If they are is there a fuse that has blown.
When your lights are on and your engine is not running you are taking the power for your car lights directly from your battery. If you leave them on long enough, you will run down your battery and your car will not start. Then you will need a jump.
Corroded, loose, or defective battery cables.
Because power from the battery, which was going to the lights, is being utilised to turn the starter motor. You should really start the car before you turn on your lights to avoid putting unnecessary strain on the battery
Dead battery?
I have a 1996 ford escort that will not start and it has a new starter on it and a new battery in it but it still will not start
Check fuel. plugs, battery, wires
The battery power is not reaching the starter. You have other problems...
Your car won't start. No electrical items will work (radio, lights, power windows/locks...)
The battery has insufficient power to crank the engine but enough power to power the lights. The starter motor needs considerably more power than the headlight bulbs.
Check battery Check battery cables for corrosion or looseness Check fusable link
First check for a corroded or damaged battery terminal. Next check the battery.
If the lights in the car come on, then at least part of the system is getting power. Check the battery connections again. Then check the starter solenoid and starter to insure that they are getting power and are working properly.