bmw 1996 328is turns off about 2 minutes after its on, it all started at night when I turned on the lights, everything on the dash went nuts and the car turn off in the middle of the highway. Do i need to replace the alternator or is it electrical??

The first thing I'd suggest doing is to fully charge the battery and then check the system voltage with the engine at about 1500rpm. It should be about or above 13.5v. Lower than that on a fully charged battery would tend to point to a failing alternator.