Display annoyance

Hi,
I'm running XP Home SP 3. Since installing SP 3, I did something to cause my
laptop display to peel back about 1/2" when I approach the left side of the
screen with my mouse. The part that peels away shows a whitened desktop
underneath. When I move the mouse away, it folds back to a full screen. It's
annoying and I'd like to get my display back to normal. I tried "full
screen" and "stretch" in the control panel but that didn't help. I try
dragging the border to the left and that doesn't help either. Also, I doubt
installing SP 3 had anything to do with it. Any suggestions?
Thanks,
jll