My in-laws Saturn doesn't start. There seems to be no power to the cab. on 1996 Saturn SL2

They jumped the car yesterday and let it run for about 30 minutes. It over heated and know there is no power to the cab. I have load tested the battery, it is good. Checked the fuses under the hood, all are good and have power. Checked and cleaned the terminals to the starter, have power there but won't start. I didn't get any power to the inside fuse box. Ground on tester may have bad connection. Any guidance?

Asked by for the 1996 Saturn SL2