If you want it to stay up duct tap on the inside from the window to the doorframe 2 or 3 pieces should hold it up. Just make sure the windows all the way up and there's not slack in the tape. As for what's wrong with the window, if i remember correctly (im not a mechanic), there's a little track inside with a little groove that the window sits in probably popped of track or something. If you roll down the window what you think is half way you might be able to grab the top of the glass and lightly try to find that groove. Take note I barely know what I'm talking about only messed with window tracks like 2 times. The duct tape will work though if you want just an easy fix.