99 nissan sentra gxe died while driving
 

just bought a 99 sentra gxw w/54K miles. while driving on highway at 55 mph the car died.

symptons: radio went out, brake light, airbag light on dash came on, car slowly died. dealer said it is the alternator and is replacing it. does this sound right? ive been reading that it could be several things, electric system, distributor, .... any help would be appreciated.