2001 sel died while driving

just to give a full scope of the problems here is the run down. 2001 sel with 3.8 engine. check engine light has been on for 2 years and no one can say why. a month ago it started saying check charging system. alternator went bad and i had it rebuilt. since i put it back on it has died twice while driving in the last 2 weeks. once i stop and put it in park it starts back up fine with no problems. now this morning i started it up and the battery light came on and it said check charging system again. i checked for loose connections and couldn't find any. the only thing anyone tells me is the computer is going bad. i need help!!!!!:banghead: