What do I do if my window won't stay open or I have a hard time opening it?

If your window is a single hung (operates up and down) this could be due to bad balancers. Balancers keep the window in the upright position

If your window is a vent (slides open) this could be due to bad rollers. Rollers are located on the top and bottom of your window or patio door to make it slide easy.