'98 nissan sentra 1.6L "a/c compressor" opinions please? ...help!!!?

About A month ago im driving down the road as usual with the ac on and all of the sudden I smell a burnt rubber smell so I pull over pop the hood and there was smoke coming from the serpentine belt. (By the way, weeks before this incident the belt would squeal and squeak time to time so I tried belt dressing and after a few days it would still start squealing again here and there but would still blow cold air fine until the day as stated above when i smelled the burnt rubber coming from the belt. My a/c has not blown cold air since that day. The compressor still comes on/ so I go buy a brand new belt but still no cold air whatsoever and I know its not a leak or low on freon. I notice that when I turn my ac on my belt runs really slow compared to when the ac is off. What do you guys think is going on from what i've told you. Ive had several ppl look at it. One guy thinks the bearings in the compressor are bad or compressor is locking up/stuck or just a bad compressor which is probably the case but a different guy thinks the compressor is still good and told me that the "harmonic balancer" is bad and needs replacement and that would fix my problem. I don't know what the hell to do! Any suggestions would be very very appreciated. Thank you ahead of time for any ones input! -also i don't even know what a "harmonic balancer" is and what it dose- could it cause the compressor to not work right and in turn not blow cold air? im just frustrated! don't know what to do!!!