If you did not activate and register your Windows 7 Starter Edition in time you will find that your desktop background wallpaper turns to a black screen. This is done to to indicate the the copy of Windows 7 Starter Edition is not genuine.

This tip will tell you how you can restore the background of your desktop to its original wallpaper.
To do so, open
Control Panel >
Display. On the left side navigation panel, click on
Change color scheme.
In the Windows color and appearance box which opens up, from the drop-down menu under
Color scheme, select
Windows Classic. Click
Apply. Next in the
color scheme drop-down list, select
Windows 7 Basic and click
OK.
This will restore your Windows 7 Starter Edition wallpaper. You should now try and register your copy of Windows to make it genuine.

This will help you, if you are facing this problem in your Windows 7 Starter, Windows 7 Starter E or Windows 7 Starter N editions.