Well I have found out that what I thought was an administrator account actually isn't!!!!
Logon to Windows 7 using your usual account.
Launch the cmd prompt - Make sure you select, 'Run as administrator'
Net user administrator p$ssw0rD
Net user administrator /active:yes
Switch User, or logoff
Logon as Administrator Password p$ssw0rD
(Your password may be different!)
Seems what you think is an admin account is really just a user account with sudo rights on certain commands.