Aluminum window will slide up, open, but not back down!

[Freespirit22]

This window will not close. But, the weird thing is. .it will open! I'm afraid to open it any higher tho'! The house is close to 80 years old and I don't know if these windows have ever been replaced. I cleaned tracks and sprayed with WD-40, but that doesn't matter on the bottom part of the track because the window won't slide into that area! Teeing to get this fixed for my

100 year old client before I leave here in ten minutes. :(

[clare]

The windows are definitely NOT 80 years old, and there has to be a "trigger" of some sort on both sides that holds the window open. You need to retract them