Initially i was having the problem with white screen as my wallpaper no matter how hard i tried to change the it with other pictures. I found one thread topic and the problem was resolved by deleting some of the values in the registry but it only allows jpeg pictures to be my wallpapers. I usually use ACD to set my wallpaper but now it can't be done.
So, if you could help me in this matter, I will be very happy. Thanks.