Part of the virus will modify the machine code，換桌 further conductive surface 致無 law，So this happens，The machine code can only be removed。
EDIT Catalogue of open bowl 啟登，Locate the following path：
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\ActiveDesktop\
Remove "NoChangingWallpaper" key to the right。
[Links]
- XP 桌布 變更 lawlessness(Is locked) – iT邦幫忙::IT knowledge sharing community
