Glant vr4 4g63 engine NEED HELP!

Last month I had my alternator replaced and it's had what I think is a sqeaking belt since. On my way home tonight I was shifting and it started as usual, but then out of no where I hear a thud of some kind. I lost power steering and heat and 3 lights came on - anti-lock breaks, battery and my e- brake. I got home and checked under the hood, and I noticed the belt isn't moving at all. It isn't broken and I can turn it freely by hand. the car still starts and runs good no noises...Does anyone have a clue what happened?
Thanks in advance, Jon.

check out www.galantvr4.org i go there for all my questions and answers

Is it a sepentine belt? If so, Is there alot of play in the belt tension, there shouldn't be hardly any, does the crankshaft pully turn? :banghead: