Head lights not working, brake, abs, traction control and door ajar warning lights on.

What year is your G6?
Has anything been done to the car recently?
Been in an accident or such?
Check all fuses and see if you can get a proper scan tool connected and try reading data or trouble codes.
If the car starts and is safe to drive, I'd recommend a shop get a look at this. You may have a control module that has failed.