May 15, 2012
Thank you for your patience in this matter. I hope I can help you replace this part!
To uninstall your original hardware, you will have to take out the screen first. Remove the screen mounting screws so that you can detach the screen from the top of the frame. Then, use the a flat-head screwdriver to depress the screen guides so that they can clear the screen track. You can then remove the screen from the frame.
After that, you can grasp and pull the screen guide so that you can remove it from the screen bottom rail. Then, insert the replacement guide where the original was. make sure that the guide spring window faces up, to ensure that the inserted end aligns properly with the screw inside the rail. Finally, push the bottom of the screen guide to "seat" it onto the screw inside the bottom rail. You will know that the screen guide is properly installed when the bottom flat end of the guide is parallel with the screen.