BobbyQ

I'm currently running Windows XP and for the past week or so my desktop background has went from my wallpaper image to a solid bg color within a few seconds of logging in. I can change theme's all days long and it changes most properties with it including icons, pointers, sounds, and window border colors but my dekstop bg stays a solid color. I can change the color but nothing else. I can right click any image off the net or my computer and set it as my active wallpaper but it never displays, and I it wont even let me choose a wallpaper from the supplied list in my display options. Any help on this would be greatly appreciated.