I believe there is a way to adjust the vinyl replacement windows, but I have forgotten how I was told when we bought them a few years back. When I open the bottom window and push it up all the way, it wants to slide back down about 3 or 4 inches. Isn't there an adjustment on the sides, and can you walk me through how to do this? They were in the home when we purchaed it. I think they came from Home Depot, but unsure of brand name. Years ago when they came out with the double hung replacement windows, we had them installed in our first home. The installer showed me how to adjust them if the lower window ever wanted to slide down when you raised it. You tilted the bottom pane out and on the inside of the stationary part of the facing?, there was a metal piece and you could turn it to tighten. I cannot remember exactly how to do it and hoped someone could tell me what it takes to do it. Thanks anyway.
(Unless you can give a brand name?)
EDIT: My brother works for a window/door manufacturer, he installed our windows...This is his advice...
Tilt lower window in towards you, IF you SEE a screw on each side (half-way up,inside the window track) Turn right to tighten, left to loosen. Turn 1/4 turn on each screw, always adjust both sides evenly!