Hey guys, I need some help to determine how to fix this serpentine belt issue. Now, when starting the car, the serpentine belt will just pop off. During my inspection, I noticed two things.

First, the tensioner pulley, and the a/c pulley do not line up with the crank pulley. I do not have alot of experience with serpentine belts, but this is like a red flag in my mind of why the belt keeps slipping off.

Second, the belt appears to be missing some of the ribs on it, aprox half.

Now, I can only replace the belt, but i don't want to replace it if that is not going to fix the problem. Can anyone give me an idea if i'm on the right track, or if it is really just the belt? This is in a 2000 monte carlo, with the 3.4liter v6 motor.