Stuff You'll Need:
- Utility knife
- Putty knife
- Pry bar
- Scrap block of wood
- 180-grit sandpaper
- Paraffin or beeswax
The sash may be sticking because it is painted shut, either from the inside or the outside. Take a utility knife with a new, sharp blade and carefully score the seam between the sash and frame.
If the sash still won't operate, wedge the flexible blade of the putty knife between the sash and the frame from the inside of the house. Use the hammer to lightly tap the knife blade around the entire perimeter of the frame and sash.
If this still doesn't free the sash, you may have to attack the problem from the window's exterior. Assuming the window is accessible and not four stories up, gently wedge a pry bar under the sill along the corner of the window. You may need to tap it with a hammer to get it in place.
Stick the block of wood under the pry bar so you don't mar the sill. Using the leverage of the pry bar, try lifting the sash -- working it evenly from one corner to the other to prevent damage to the window.
With luck, the window is now open and you can examine the tracks. There may be paint buildup or burrs (rough areas on the metal). If that's the case, lightly sand the area and apply paraffin or beeswax to keep things moving smoothly.
For more do it yourself ideas, purchase Joanne Liebeler's Do It Herself
From "Joanne Liebeler's Do It Herself, Sunset Books