supraboi18

i got a stock 97 240sx ka i was driving today and all of a sudden radio turn off and all the dash light pull aside and the neg terminal plastic cover started burning off so putted in a new battery and it melted the negative post im thinking i got a shorted from starter or alternator but no. So did anyone ever experience this problem or know what it could be to cause the car not to have power and melting the neg wire. And i havent mess with anything but putted a new starter in 2 month ago

Thanks