You can turn the 32-bit SKUs of Windows Vista into the 64-bit editions of the operating system. But it will cost you... Vista is the first client platform that features both the x86 and x64 flavors simultaneously, on the market since the moment of launch. Although Microsoft delivers the operating system on a single DVD, the media only contains either all the 32-bit editions, or all the 64-bit SKUs, but not all of them.
In this context, jumping from the 32-bit version of the platform to the 64-bit one is not as streamlined a
process as it might seem. The Windows Vista Anytime Upgrade options do allow end users to easily jump from a low end edition of Vista up the scale toward and to the Ultimate edition, but this is valid only from one 32-bit SKU to another 32-bit SKU. Respectively from a 64-bit variant to a more feature-rich 64-bit variant of Vista. The move from 32-bit to 64-bit is not supported by Microsoft, whether it is referring to a shift between SKUs, or from one x86 edition to its 64-bit counterpart.
With a little exception, of course. “As long as you have purchased a license of Windows Vista, you can order an alternative set of media (64-bit) if you need the other edition instead, for a nominal fee. You would go to: http://www.microsoft.com/windowsvista/1033/ordermedia to do this. Once there, you will need to supply the 25-character product key that came with your purchase as well as: your name, your shipping address, credit card information, media choice, your e-mail address. After that, you just need to wait for the alternative media to arrive,” explained Eric Ligman, Microsoft US Senior Manager, Small Business Community Engagement.
In this manner, you are effectively ordering the Windows Vista Alternate Media. “You can order either of these alternate media for a minimal fee, including shipping and handling. To order, you'll need to supply the 25-character product key that came with your purchase,” reads a fragment of the description of the Windows Vista Alternate Media.
Microsoft, Windows Vista, SKUs, 32–bit, 64–bit