XP Wallpaper
 

I have a desktop that is about 2 years old with XP. I can set a picture from the internet as wallpaper on one user's account and it does not affect the wallpaper for the other user.
I got a laptop a few months ago, and whenever one user changes wallpaper, it also changes the other user's.
What can I do to allow each user to have different wallpapers?
Thanks