Really? Again?

My Ford Taurus started making some odd noises the past few times I've driven it. I had to run to the grocery store tonight and the noises were definitely louder, bit of a grinding, ball bearing sound. Well on the way back home the noise stopped, it squealed, then the battery light came on. THen a bunch more warning lights and I noticed the headlights dimming.

I lost power steering as well, luckily it stayed running long enough to get home. I was going to back it into the garage to make it easier to jump start if we had to. I flipped from drive to reverse and the engine died. I had no more battery power left so I just pushed the car into a parking spot on the street. I popped open the hood and saw that the serpentine belt was not looped around the alternator.

I pulled on the belt and it wasn't broken so it looks like it just came off somehow...which is rather odd. It was already quite dark outside so I didn't feel like messing with it. I may try and fix it myself, but I'm concerned at the rattling/grinding sound I heard. It is possible that some part of the tensioner pulley or something actually broke. If this is the case, I'd have no clue whatsoever on how to fix that.

My car knows I will be getting a tax refund when I do my taxes next month, so it fired a preemptive strike against that.