Whining and steering belt grabbing

I thought the idler arm pulley was bad and then I broke a belt. I was told I needed a new alternator. So, I replaced both. Then I was told I only had one bolt holding in alternator. But I have this whining and belt grabbing. At first it quit after a few minutes, but now I keep feeling the steering belt grab when I turn the wheel. Is it because the alternator is moving out of place or something else?