There are activation problems in the Windows Anytime Upgrade heaven. All editions of Windows Vista are basic versions with the sole exception of Ultimate, according to Microsoft. The Redmond Company introduced, concomitantly with the launch of Windows Vista, a new feature designed to enable users to develop a lower end edition of the operating system. There are limitations set in place, for example, users will not be able to upgrade between 32-bit and 64-bit versions of Vista. Additionally, as shown by the image towards the bottom, Vista Home Basic can only upgrade to Home Premium and Ultimate, while Windows Vista Home Premium and
Business can only "grow" to the Ultimate edition.
By including all the editions of Windows Vista on a single installation media, Microsoft has streamlined as much as possible the upgrading process between editions. If the Vista DVD has the "Includes Windows Anytime Upgrade" logo, then the media is what Microsoft refers to as the "Windows Anytime Upgrade (WAU) DVD" and users will be able to swap between editions.
"Windows Anytime Upgrade is an upgrade option that lets you upgrade a basic version of Windows Vista to a version of Windows Vista that contains more features. This upgrade option requires that you purchase a Windows Anytime Upgrade package for the particular version of Windows Vista. The Windows Anytime Upgrade package includes a license agreement and a product key for the version of Windows Vista to which you are upgrading," Microsoft informed.
However, activation issues can follow the upgrade. "Consider the following scenario. You have a computer that is running a version of Windows Vista. You upgrade to another version of Windows Vista by using the Windows Anytime Upgrade (WAU) DVD. Then, you try to activate Windows Vista over the Internet. In this scenario, you receive an error message that resembles the following: The Windows Vista product version product key you typed is invalid for activation," Microsoft added.
According to the Redmond Company, the problems are connected with the Vista product key, which can be either incorrect or the same as the original, upgraded version of Vista. Users will have to contact Microsoft Support or their computer manufacturer to finalize the upgrade process.
Source:→ SoftpediaMicrosoft, Windows Vista, Vista Upgrade, Windows Anytime Upgrade