a/c compressor-96 blazer

i have a 96 blazer and it had a new motor put in and a tranny installed within the last year or so. all is great except yesterday when i drove to the gas station i heard a visicous squeel. it appears to be coming from the ac compressor? does anyone know about this noise? does the entire compressor need to be replaced or maybee just a clutch? any ideas?

does this only happen when u turn on the a/c....turn it on and look at the compressor with the engine runnin....if the belt just slides over the pulley and the compressor dont turn and smoke is goin everywhere then yeah u need a new compressor

a/c never worked since i bought it. there wasnt and smoke that i saw and the pulley would rotate intermittently. i did however replace the compressor and just like that there is no more squeek. this job took me about 20 min to do. only because there wasnt any freon in the system.

do you think that if i recharge the system my ac should work? and why would there be no freon in the system? is there a possibility that it just needs recharged or doesn that mean that i have a leak?
and last but not least.....when i turn the ac on should the clutch engage on the compressor if there isnt any freon in the system? because it does not

yeah u gotta have freon in the system for it to work and the squallin u heard before since now i nkow there was no freon in its was probably the pistons in ur compressor lockin up cuz the freon has oil in it and if u have none then ur compressor gets no oil....and the reason it doesnt work with no freon in it is because there is a pressure switch in ur lines and if there is no freon in the lines (again no oil) to make adequate pressure the switch wont let ur compressor kick on to keep itself from lockin up....get it charged cuz the doit urself kit will just cost u another compressor and it should work and have the place put some dye in the oil so u can see if u have a leak, then it should work