Helipng the widowed neighbor go through her houses presale inspection report helped me learn something. I'm pretty good with doors and windows, 84 has a great training program and I was the door and window guy for six months, the factory reps teach you a lot. Both of our houses were built by the same local builder almost 40 years ago using Andersen Narrowline windows. I've looked at using Andersen's Renewal program to replace all of my windows, but that will cost a bit while being far less intrusive than replacing the whole window.
In any case, she had two windows where the strings that keep the windows up were not retracting. Found a youtube that explained why and how to replace the "cartridges". It was courtesy of a place that specializes in door and window hardware. What would be 300-400 hundreds looks to be a hundred or two if you hire a guy.
Linking that vid because the company associated should be in any handymans list.