desktop image problem of friend

OK. this guy's dad looked online @ a pic of a canister, and did "something", and the desktop ended up being that pic. Now he can't change it. when he goes to properties>desktop>, everything is "blurred out" (inactive; not "clickable") in that window, he says, incl. the list of the desktop images where one normally clicks to change the desktop. he restarted the pc, and the canister is still there happily.

using win xp.

any ideas what he/dad can do?
thanks for any help.

 

You could try changing the wall paper in the registry.

The system stores the usual background wallpaper bitmap in the HKEY_CURRENT_USER\Control Panel\Desktop\Wallpaper registry key.
If Active Desktop is enabled and a different background picture eg a JPEG file the system stores this wallpaper in the HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Desktop\General\Wallpaper registry key.

Just be careful delving into the registry!! Take a backup first.