Electrical problem

I have a 1994 buick roadmaster. The other day i pulled out of my driveway, drove up to the stopsign and my car completly died. It did this a couple more times and the last time it did this i couldnt get it to start back up. I had to have somebody give me a jump and the car started right away but when i took the positive cable off it died again, but it started back up. The next day i took it to a local mechanic. He said that my battery was bad and my starter had a short in it. I took the battery back to sears because it has a warranty on it, its only about 5 months old. The guy at sears said there was nothing wrong with the battery. I also took it to a local auto parts store before i took it back to the mechanic and they also said that it was ok. I took it back to the mechanic and he tested it again and it tested good for him to. The mechanic replaced my starter and said that it should be ok now. I have never had a problem with the starter and i was wondering if a bad starter would cause the car to completly die with no power whatsoever.

A bad starter will not cause an engine to die. Sounds like a bad alternator. Have a competent technician test the charging/starting system.

Thanks for your respnse. Thats what i thought but he said that the alternator is ok. He charged me 300 dallors (not including labor) for this starter two days ago and its grinding and squealing already. I feel like i paid this guy 500 bucks to ruin my car.