HELP Car died after loud sound like pop

Sorry guys I re read my aove question and fixed the typos:
2007 Chrysler 300 Touring 6-cylinder. I Haven't had any troubles, went to crank it yesterday and it made a loud horrible backfire sound and everything shut down. The car alarm wont work, the lights and everything is dead. It wont crank and my brother had to look in the manuel for the swtich to put it in gear to move it into the yard for safety. What's wrong?

Thanks Docfixit for responding. The car has been driving great smooth ride and all. Drove fine all day got in it to crank it up and move it into the garage and upon cranking ti made a loud horrible noise that sounded like a backfire or gunshot. I dont know much about cars, but I do keep the oil changed and I had it serviced in Nov 2010 and there were no problems. I have no clue what it could be there was no smoking, but I called a dealership and they said to replace the battery. I'm going to head out to get htis done and keep you posted on the outcome. If you have any suggestions or comments pleae advise.

What ended up being wrong with your car? My 300 just did the same thing!