Chevrolet Repair: serpentine belt, crank pulley, tensioner pulley

Question
2000 Malibu 68000 miles.
My serpentine belt has been squeeking for a few weeks.  Tonight, when I started the car, I think it slipped off the large bottom pulley and began to smell of burning.  I immediately turned it off. Bottom pulley or wheel seems to be loose. The belt is loose. I think it will it have to be towed for repair.  What may have been the cause?  

Answer
Hi Robert, This would be which ever bottom pulley your refering to. There are a few pulleys on this car, A/C compressor, crank pulley, and the tensioner pulley all located very low. I have seen a few A/C compressor pulley bearings go bad and cause this to happen. You'll need to see which one is no good and repair it.

Hope this helps

Mark