Wing window removal?

I want to buy some wing windows at a salvage yard because my AC is nothing but problems, and I tried to get one off once but I couldn't figure it out. Do you have to take out the whole rail from inside the door? I had to brake the window on the one at the salvage to get as far as I did and I still coulnt get it all the way out. If this is an all say job, it isn't worth it but i don't se why it should be. I gues I am missing something simple. ( usually the case when I am stumped)
Please help!
Thanks.

there are two screws from front side of door frame that hold wing frame in and then there is one nut down low on door inner frame to remove then windown n frame just slips out back and to inside of door easy job about 15 mins

Just to clarify, the vent window assembly includes the front track for the roll-down window, as well as its own framework. You need to take the door panel off to access the bolt at the bottom of the track. You should also remove the outside weatherstrip trim molding at the bottom of the main window. Do the job with window rolled down. The last detail of removing and the first of installing involves feeding the tab at the bottom of the track past the top of the window (which is why removing the trim helps a lot). After that it's simple, just push it into place, making sure that the window gets into the track, and that the rubber gasket goes into place on the door frame correctly without creases. The first one will take you a while; the second one will meet crazyray's 15 minute estimate.

To minimize leaks in the vent windows, you can adjust the position of the glass somewhat by loosening the screw in the top hinge. Also make sure the latch mechanism isn't loose. It's held together by a hidden screw inside the post of the latch. You can push out the little roll pin in the handle, pull it off, and then tighten the screw with a screwdriver. Make sure you reinstall the wavy washer under the handle when putting it together. A little silicone grease on the glass-to-rubber mating surfaces also does much more good than you'd expect.

I have a set of these windows that moves from Jeep to Jeep. Some people hate them but I love them, leaks or not.