I thought I'd clean my windows and took the screens off.. Now I can't get them back on. I know how they are supposed to go on, they just don't fit. They have a groove they are supposed to go in - slide them in up the top, push them over so the side fits in then pull them down a bit so they fit properly. But I can't them to go in up the top at all - the window isn't wide enough. They are 10 year old aluminium sliding windows. What is the trick?? This is frustrating the hell out of me.