The ability to upgrade directly from earlier version of Windows operating system to Windows Vista will depends on which version of Windows you already have and which Vista you plan to get. Only certain editions of Windows XP variants support direct in-place upgrade without clean install. All pre-XP Windows OS (including Windows 9x, Windows Me and Windows 2000) is unable to directly upgrade to Vista without performing a clean installation.
Even for Windows XP, not all editions support in-place upgrade option to Windows Vista. Check out the following table for which versions of Windows XP that are capable of in-place upgrades to which versions of Windows Vista.
|Windows Vista Home Basic||Windows Vista Home Premium||Windows Vista Business||Windows Vista Ultimate|
|Windows XP Professional||No||No||Yes||Yes|
|Windows XP Home||Yes||Yes||Yes||Yes|
|Windows XP Media Center Edition||No||Yes||No||Yes|
|Windows XP Tablet PC||No||No||Yes||Yes|
Yes mean you will be able to perform from this edition of Windows XP to the corresponding version of Windows XP. If it’s a No, you have to clean install Windows Vista.
Note also that 64-bit Windows XP x64 also cannot be upgraded in place. Only Windows 2000 and Windows XP are eligible for the upgrade options to Windows Vista. Any other version of Windows will require you to purchase a full license.
Although you can’t perform an in-place upgrade, upgrade pricing for Windows Vista DVD license may still be applicable if you own any version of XP or Windows 2000, such as Windows 2000 Professional or Windows XP Professional x64. But note that if you purchase upgrade version of Windows Vista Home Premium, Home Basic and Starter edition, you will always need to perform in-place upgrade to Windows Vista, as clean installation won’t work in these versions.