you have "double-hung windows." try this link http://www.service.com/PAW/morgue/real_estate/1994_Aug_26.HOME26.html

(I got this from someone else's reply to a question like yours, which I read in this message board- somewhere in the second page of these messages)

I tried the website you suggested, but the link was incorrect. I have been looking for something to replace the old weight and pulley system. I know something is available, but don't know what it's called, nor can I find it at my local home center. Can somebody help?

If you scroll down through the posts, you will find the message where I got thie link- maybe you could follow it from the origonal post.

the gist of the information at that link is that the pulley system is easy to repair. you can access the pulleys by taking the side trim off the window so you can see into the wall. You can replace broken sash ropes with new cotton rope or chain. To take the sash out, you remove the vertical sash stops that form the channel the sashes go up and down in.

If you want to replace the pulleys with something else, maybe Marvin Windows and Doors is what you are looking for. They have something called a Magnum Tilt Pac which apparently is a replacement sash that you can use in existing double hung window frames. http://www.marvin.com/

hi i have installed the marvin tilt pac and they are a good replacement for the rope and weight systems. they are an easy installation for the do-it-yourselfer.goood luck on your project!