Changing wallpaper problem
Windows 7 does include the option to change your wallpaper every 10 seconds, up to once a day. On the desktop, right-click in an empty space, choose 'Personalize', then at the bottom edge of the screen, click on the blue words 'Desktop background'.
Then at the top-right of the window, click on 'Select all'. Now in the 'Picture location' box, choose the folder with your wallpaper pictures in. Down at the bottom of the screen, 'Change picture every' , choose the rate you want your wallpaper to change. Hope that's what you wanted.