Slipping Serp. Belt

Hey guys I have a 98 classic with about 120k miles on it. My serpentine belt was replaced @ about 80k miles after my brother cracked the water pump. I have been having intermittent squealing problems when the A/C is turned on and now I am getting complete slipping of the belt when it rains. It is slipping at the crank pulley because I loose power steering and the volt meter drops. I live in Florida and it eather rains hard or not at all, the squealing was annoying but now loss of power steering is dangerous and annoying. I have tried tightening the belt numerous times with no luck. Is it possible that i could have a bad belt or that it has somehow become "glazed" or hardened somehow by the slipping or hot weather? Please let me know if any of you have any experience with this or thoughts. Thanks guys.

relpace the belt. cheap an easy first. if you have had that beelt on there for 40,000 miles then it is probably time to replace it anyway. take a look at your pulleys and make sure none of them have rust on them.

If you do the belt do the idler pulley, thats the one under the PS pump that you use to adjust the belt, $17 from the dealer last time I bought them.

Right about the idler pulley. Change that and squeaks be gone...

After checking the idler pulley, check the harmonic balancer. Make sure it's not separating. That causes a nasty squeal and would derail the belt.