potentially the user profile could be broken which can result in other errors which you may not have recognized yet.
run regedit and have a gander at these keys:
user key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\
Explorer]
system key: [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\
Explorer]
name: NoActiveDesktop
type: REG_DWORD (DWORD Value)
value: (0 = disable restriction, 1 = enable restriction)
there would not normally be any "activedesktop" policies in the right pane and you can delete any there that you see.
however you force disable active desktop by adding the NoActiveDesktop value and setting it to 1 (which enables the restriction).
this may not work if you work with other policies - which can overwrite the settings you make...
