My friend hooked up his battery the wrong way and his car will not start (or even attempt to turn over), radio does not go on, dash lights do not go on. Yet there is a beeping sound, the same beeping that starts when the headlights are on and key is still in the ignition.

i'm wondering what might have happen. i know that fuses probably blew but i don't know if anything worse could have happend, i don't know how this car was built. Does anyone know if very bad damage could have occured?