" Older windows have counterweights hidden inside the window frame to hold the window in place when raised. When the rope connecting the window to the weight breaks, the window will no longer stay up. Here's how to fix it. To get access to the window weight, you need to first remove the casing covering the access door. The casing is called a front stop and it holds the sash in place. In this case, the front stops are held in place by round-headed screws. Before removing the screws, use a sharp utility knife to cut the paint along the edge of the front stop. Cutting the paint with a utility knife will allow you to remove the front stop with minimal damage to the paint. Using a hammer and a small flat pry bar, work the front stop away from the frame. Work slowly to avoid damaging the finish. Once the front stops are removed, lift the lower sash and rotate it out of the window frame. Remove the old sash cord by lifting the sash cord knot out of the channel on the sash from both sides of the window. Under the front stop, you'll see a pocket cover. Remove the covers to reveal the window counterweight. Fish the counterweight out from the well and set it aside. Tie a light fishing line to a small fishing weight and slide it over the pulley and lower it down into the well. When it reaches the level of the pocket, tie the new sash cord to the fishing line, and then gently pull the sash cord up and over the pulley and out of pocket. With the window disassembled, it's a good idea to replace both sash cords even if only one is broken. Tie the end of the new sash cord to the counterweight. Pull the sash cord to raise the weight three to four inches from the bottom of the window well, and then, mark the sash cord at the location where the sash cord leaves the pulley. You do this to allow for the stretching of the cord, preventing the window weight from hitting the bottom of the pocket when you raise the window all the way up. Next, measure the distance from the top of the window sash to the space to the knot in the channel. Add this length to the length of the sash cord. Mark it, tie a knot just below the mark, and cut off the excess sash cord. Replace the well pockets and screw them in place. You'll need help for this next step. With somebody holding the window sash for you, push the sash cord into the channel in the sash, and slide the sash back into the window. Rub beeswax over all the surfaces that the window sash slides against. The beeswax acts as a lubricant. Replace the front stops by pressing them gently into position, and replace the screws. Raise and lower the sash. The window weight should not hit the bottom of the well when the window is fully raised. And the window should rise and fall easily. Touch up the trim with a fresh coat of paint, and your window will be like new."