[DaveC2003]

Click Start-Run and type:

regsvr32 /i shimgvw.dll
regsvr32 /i shell32.dll

See if the problem is resolved. If not, proceed further:

Is Active Desktop Wallpaper set? If so you can remove from the registry (for
stand-alone systems).

Create a System Restore point, or take a valid registry backup.

Open Regedit.exe and navigate to these locations one by one:

HKEY_CURRENT_USER\Software\Mic...
HKEY_CURRENT_USER\Software\Pol... Panel\Desktop
HKEY_LOCAL_MACHINE\Software\Mi...
HKEY_LOCAL_MACHINE\Software\Po... Panel\Desktop

In the right-pane, delete the following values if they exist:

1. Wallpaper
2. WallpaperStyle

Close Regedit.exe and re-login.