The authentication method will be much improved...

> the old actvation code method that I had doesn´t works anymore, with
> windowsupdate. when I´m installing SP@, it gives a "not authorized code"
> message.. (instead of wrong key number, etc)

You can't use any of the activation keys on the bad list (yours must have gotten around somehow, either that or MS has started using a good list), you need to generate a new one somehow...