I have seven older vinyl windows that all have the same problem. All of the balance rods are under tension, but the shoes that slide in in the tracks do not move. I can't get to to move in any direction and I can't figure out how to remove them from the frame. Also every one of the metal parts that attach to the bottom corners of the sashes is broken. I'm hoping you guys might have that trim piece as well. I'm a contractor and have some experience with this stuff but I've never seen this setup.
Parts identification would be great! Also, any kind of resource you could point me towards to help me understand this setup would be greatly appreciated!