Heres a nice little program I made to piss off my friend to the max. He changed my wallpaper one time and thought it was funny. So I made this little .NET app to pretty much do the same to him... though in excess. Making it so he is unable to change his wallpaper back, even if he restarts his computer.
If you want to try it out, feel free. Its not dangerous in any way, and if you wish to reverse the affect of the program, do the following:
Open Task Manager (CTRL + ALT + DEL) and kill the process called "scvhost.exe" (Be sure not to kill svchost.exe, I named scvhost similarly to svchost(A system executable) for confusion.)
Open RegEdit (Start>Run>"regedit") and go to "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" and delete the entry "MicrosoftHostService"
Go to C:\WINDOWS\system32\ and delete scvhost.exe and tfc4rnOeHO.bmp
DOWNLOAD HERE