1995 Mitsubishi Galant when do you need to fix the water pu

I have replace the same belt every year for the past three years, (it's the bottom belt that goes on the right side of the engine). Every time it is replaced it sounds fine for a week and then starts to squeal again. When I turn on the car it will start squealing then stop, if I come to a complete stop and then start driving again it squeals and if I turn on my A/C or heat it does the same.

Last week the belt broke again causing my car's power steering to go out, my car to over heat, and my battery and brake lights came on. I had the belt replace but as soon as they turned the car on again it started to smoke, the pulley wouldn't move, there is a mark in my belt already, and it squeals. The people who put the belt on says that the alternator locked up, but another man said that it is my water pump that I need to replace because it is not turning that pulley.

What does it sound like to any of you? The water pump or the alternator?