Microsoft does not allow users with windows 7 starter edition installed to change their wallpaper / background.Below guide will show you how to tweak your registry to change wallpaper / background in windows 7 starter,no 3-rd party tools need.
1.Click Start then type regedit then press Enter to open registry editor
2.Browse to HKEY_CURRENT_USER\Control Panel\Desktop ,in the right pane ,double-click wallpaper and change it’s value to your own wallpaper file(eg: C:\wallpaper\wallpaper.jpg ) ,then click OK
3.In the left pane ,right-click item Desktop and click Permissions.. ,then click Advanced
4.Go to Owner tab and change the owner to yourself (Only 2 choices,one a administrator one is your user account)
5.Click Add to add everyone to security group,then select account everyone and grant it the Read permission(Do not set to Full control or special permissions)
6.Click Advanced again,then clear the check box of Include inheritable permission from this object’s parent ,and click Remove on the popped up window , then click OK twice then exit Registry Editor
7.Go the folder (Eg: C:\wallpaper ),copy your wallpaper file to here and rename to wallpaper.jpg ,then reboot to enjoy your new wallpaper
8.To change your wallpaper ,log off then log in is ok ,no reboot needed.