Vista Ultimate Media Centre Edition and Media Sharing security errors

>I am logged in as Administrator Administrator is a member of the local
>Administrators group.
>
> When loading Windows Media Centre I get this error message:
>
> Windows Media Centre
> x You are currently logged on as a Guest. Windows Media Centre requires a
> non-Guest account. If you need to change your user account type, contact
> the owner of this system.
>
> I have windows firewall disabled
> The internet is working fine
> I have UAC disabled ( I also tried enabled, made no difference)
> I have windows defender disabled
>
> Network Discovery = ON
> File Sharing = ON
> Public folder sharing = OFF
> Printer sharing = OFF (no printers installed)
> Password protected sharing = OFF
> Media sharing = OFF
>
> And if I try to select Network and Sharing Center/Media Sharing/Change...
> I get this error message
>
> Windows Media Player
> ! You are logged on with a user account that does not have sufficient
> permissions to turn on media sharing.
>
>
> I tried right clicking Media Centre Edition and selecting RunAs
> administrator, I get the same "Windows Media Centre requires a non-Guest
> account" error message.
>
>
> --
> Regards,
> Hamish Ahern.
>
>