misterbean

My mother has a 1973 or '74 240z that seems to be having electrical problems. It started on Friday when she was driving it and the radio kept turning on and off, but everything else worked properly. Then yesterday when she tried to start it she said the engine started to turn over and then stopped, and none of the electrical stuff worked. Today I tried to jump start it so I connected it to my car, and tried the headlights and some of the other electrical stuff and everything worked, so I tried to start it up, there was a click, and everything turned off. Now none of the electrical stuff works, but the battery in my car is fine. I checked the fuses in the console, as well as the connections for the ground coming off the battery and the positive coming off the battery and they all seemed to be alright. Any thoughts?