Laptop won't turn on.. After being unplugged and left in a cold car for 9 hours, won't turn on

Question

After being unplugged and left in a cold car for 9 hours, won't turn on after then plugging into electricity. Has a new battery purchased 6 months ago. Electricity outlet working and checked connection of plug to be sure it's tight but no lights on the computer at all. It has been plugged in overnight but still no lights and won't turn on.Compaq