Windows Vista comes to the market in an array of flavors. In addition to the core Windows Vista editions Home Basic, Home Premium, Business and Ultimate, Microsoft is also offering the Starter and Enterprise versions, as well as two variants for the European market of Home Basic and Business. And as this wasn't enough all Vista editions support both 32-bit and 64-bit architectures.

However, the one downside of Microsoft's luxuriant offerings with Windows Vista is the inherent consumer confusion. One prime example in this regard is the fact that upgrades from Windows XP to Windows Vista are limited. And when it comes down to upgrading from 32-bit Windows XP to 64-bit Windows Vista, users' options are inexistent altogether. Still, James Senior, a Microsoft UK technical specialist revealed that it can be done, going against the word of the Redmond Company.

"From the Vista ask the experts session Matt and I did this morning we had a question about upgrading from 32 bit XP running on 64bit hardware and the ability to upgrade the OS to 64bit Vista Business. The answer to this question is that you can upgrade and this is what's supported: retail upgrade supported (using FPP or discounted SKU), volume license upgrade supported (using Volume Licensing-purchased Upgrade SKU) and available via limited time coupon offer from OEM (Express Upgrade)."

Microsoft fails to see eye to eye with Senior in this manner. In the Upgrade Paths from Windows XP to Windows Vista Microsoft does not offer a solution to swapping 32-bit XP fro 64-bit Vista. Furthermore, the company claims that such an upgrade cannot be done.

"You cannot perform an upgrade from a 32-bit version of Windows XP to a 64-bit version of Windows Vista. However, you can use an upgrade copy of Windows Vista to perform a clean installation of a 64-bit version of Windows Vista," Microsoft informs and goes on to day that users should "begin the installation by inserting the 64-bit Windows Vista DVD into your computer's disc drive, and then restart your computer. You must start the 64-bit Windows Vista installation from the Windows Vista 64-bit disc because Windows installation will not run on a 32-bit version of Windows."

Knowledge Base article 930891 also reveals that the 64-bit Windows Vista installation disk cannot be used to upgrade from a 32-bit Windows XP. "This behavior occurs because Windows operating system upgrades are supported only between matching operating system architectures. A 32-bit version of Windows XP does not recognize the 64-bit Windows Vista installer engine," Microsoft explains in 930891, and states that a custom installation is the only option for users that still want to use an upgrade 64-bit edition of Vista with their 32-bit Windows XP.