I recently been having problems with my computer.
Somehow I have worked through it to getit back on track. I believe I had a virus.I have a teenager in the house that I have banned from getting on here so I could figure thing out. I had reinstall the printer and the sound system, also the desktop background wouldn't work but I finally got everything back to normal. I have installed an anti-virus/anti-spyware. Anyway I am having trouble with my desktop background. It won't let me put on a background either from the ones window xp offers or the ones on the internet. I have tried everything that I know. Can someone help me? Thank you

Try this:

http://www.kellys-korner-xp.com/xp_tweaks.htm

142. Right hand side
Allow Wallpaper/Background Changes