Grip the vinyl paneling at the base, where it meets the vertical receiving track.
Inch your way along the receiving track, pulling the paneling out as you go.
Locate the receiving track on the opposite side of the panel. Pull the vinyl panel out of the receiving track the same way you did in step 1.
Insert the tip of your flat-head screwdriver in the seam at the bottom of the panel.
Pry out with the screwdriver to pop the rear fiberglass frame of the vinyl panel out of place.
Pull the frame down and remove the vinyl panel.