BleepingComputer.com: Desktop Background Problems

On one of my computers, the background theme has somehow been set to what I asssume is a webpage. I am not sure, but my best guess is that one of my sons inadvertently, or unbeknowingly realizing the consequences, clicked on something on the web that set this page as a background.

I am unabe to remove this desktop background. I have gone to the display properties feature by right-clicking on the desktop and clicking properties. Under the desktop tab, the backgound box with the different background themes cannot be entered and changed. I have also gone into the Windows files where the background themes are stored and that particular background is not stored in that file.

I have done a System Restore without luck and have ran SpyBot, Ad-Ware SE Plus, and ADWare Alert without correcting the problem. I also ran my antivirus software without correcting the problem. I also went into msconfig and unchecked any startup programs that I did not recognize and that did not help.

I do not know how to go further to solve this problem.