There is a squealing in my car?

I have a 97 ford Taurus, we had a squealing in my car, we thought it was the belts, but they are new. we change the alternator, the squealing stopped for a day. came back again, we thought it might be the pulleys and changed those, still no change. the squealing is constant from the moment we start the engine, when we idle the noise grows quite, when we speed up it becomes intense. when we turn it changes pitch. I have no idea what is wrong with it, we do have air conditioning, and the water pump does need replacing but it does not have a leak its just old.