2001 bmw 330i alternator help!!!!

Okay, here is what is going on. I had loud whirling/rubbing noise constantly driving me nuts, when i had my new tires put on, the tech said it was the main tensioner and ac tensioner causing the problem. They changed them, but informed that i would need a new alternator in a about 6 months. The problem subsided, however, within a day, the noise came back. I called the tech and he informed since the new tensioners were installed it could have affecting the alternator and made it worse and that is causing the noise. Today, when i was driving home my radio/clock went black. I made it home, 2 hours later i started the car and the clock is back on. 2 questions. Is this safe to drive(i am assuming not) and when i bring it in, can they tell if the alternator is the problem or is it the belt. Also is the alternator connected the serp belt? I am beginner , so please explain simply. Thanks