Q: Reversed jumper cables and now car won't start even with a new battery.

A number of things may have occurred when the jumper cables were reversed. The battery cables themselves may be fried and require replacement in order to start the vehicle. The PCM or the main computer in your vehicle may also have been fried in the process but the battery cables are the most likely cause. Even more unlikely but still a possibility is that your starter is even damaged. The first thing I would recommend is to have a qualified professional inspect your starting system for any signs of burning. These signs will be most noticeable where plastic exists such as the battery case of the old battery and the insulation of the battery cables. Have the technician also inspect the fuse box for any blown fuses or signs of burning in that area as well.