1984 Subaru Other

I have a 1984 Subaru GL 4 wheel drive wagon that has about 146,000+ miles on it.
The car battery was a little low and my son decided that he was going to help me by trying another battery. When he put the battery in, he hooked it up with the positive cable on the negative post and the negative cable on the positive post. Then he tried to start it. He said he heard a click. That is all I could get out of him.
When I put my key in the ignition, it starts chiming. However, no dash lights come on nor will it even attempt to start.
HELP ME. Please. I don't know where to start to find the problem. I don't know where any of the circuit breakers are on this car but I have checked the fuses and they are okay.
July 31, 2007.

He has most likely killed the computer, might pay to get it checked. Thanks

Aug 3, 2007.
Check the fusible links. They are the safety device that prevents damage to components when there is a short or other goof up

Mar 23, 2010.