Set black wallpaper

wallpaper.bat which contains:

xcopy black.bmp c:\windows\web\wallpaper\

regedit /s wallpaper.reg

wallpaper.reg contains:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Control Panel\Desktop]

"Wallpaper"="c:\\windows\\web\\wallpaper\\black.bmp"

And black.bmp is one black pixel image