nope it wont change ..
i've tried every thing i know.
it's driving me crazy
ok
i delete every thing in %USERPROFILE%\AppData\Roaming\Microsoft\Windows\Themes\
than i change to default windows 7 theme and that blue wallpaper (TranscodedWallpaper.jpg)
came back..
so there is no problem with locations.
when i logof or turnof wallpaper shows but on desktop only sold color.