Here is a picture.

Austin, can you remove the handle? It might be stripped. If so, you just need a replacement handle. I had windows like that & the mechanism is mounted from below. If it's not a stripped handle, removal is the only option, I believe.
Don

A lumberyard should be able to order you replacement operators if that is what is required, the are fairly easy to remove with the window open.

That hardware was probably made by TRUTH, if that helps. You will need to get the window open somehow to be able to service the hardware.
It's probably painted shut or brick-bound. pry gently to make it swing open while someone inside turns the spinning handle and maybe it will bite.

Good luck

I live near Cinti OH. I buy all of my window parts (esp my casement windows) from Pickens Window Service in Cinti. They have thous of window parts. Our windows are also about 25 yrs old. Ours are Malta and they look a lot like yours. You could probably order the parts that you need from Pickens. Here is the URL www.pickenswindowparts.com. They have always been able to help me with the windows that we have ie screens, cranks, etc. Very nice and easy to deal with.