I have a 2007 g6 convertible. About a month ago I was driving and the car shut off. Radio was still on and I didn't notice it was off until I went to move and it didn't go. It wouldn't start initially but after a few tries I was able to peddle it home the 1/4 mile. Now when I go to start the car there is an arch between the terminal and the battery that is sparking. It clicks once and sparks and nothing else. Where should I start looking? I have no idea where to begin. There is also melted metal at the terminal so I'm thinking there is a short somewhere. The terminal still has contact.