Windows Thin PC

Windows 7, a major release of the Microsoft Windows operating system, was available in six different editions: Starter, Home Basic, Home Premium, Professional, Enterprise and Ultimate. Only Home Premium, Professional, and Ultimate were widely available at retailers. The other editions focus on other markets, such as the software development world or enterprise use. All editions support 32-bit IA-32 CPUs and all editions except Starter support 64-bit x64 CPUs. 64-bit installation media is not included in Home-Basic edition packages, but can be obtained separately from Microsoft.

According to Microsoft, the features for all editions of Windows 7 are stored on the machine, regardless of which edition is in use. Users who wish to upgrade to an edition of Windows 7 with more features could use Windows Anytime Upgrade to purchase the upgrade and to unlock the features of those editions. Microsoft announced Windows 7 pricing information for some editions on June 25, 2009, and Windows Anytime Upgrade and Family Pack pricing on July 31, 2009.

Since October 31, 2013, Windows 7 is no longer available in retail (except for the Professional edition preinstalled):

Mainstream support for all editions (new features and bug fixes) ended as of January 2015, but extended Support (security updates) will continue until January 2020.

The main editions also can take the form of one of the following special editions:

In-place upgrade from Windows Vista with Service Pack 1 to Windows 7 with is supported if the processor architecture and the language are the same and their editions match (see below). In-place upgrade is not supported for earlier versions of Windows; moving to Windows 7 on these machines requires a clean installation, i.e. removal of the old operating system, installing Windows 7 and reinstalling all previously installed programs. Windows Easy Transfer can assist in this process. Microsoft made upgrade of Windows 7 for selected editions of Windows XP and Windows Vista. The difference between these SKUs and full SKUs of Windows 7 is their lower price and proof of license ownership of a qualifying previous version of Windows. Same restrictions on in-place upgrading applies to these SKUs as well. In addition, Windows 7 is available as a Family Pack upgrade edition in certain markets, to upgrade to Windows 7 Home Premium only. It gives licenses to upgrade three machines from Vista or Windows XP to the Windows 7 Home Premium edition. These are not full versions, so each machine to be upgraded must have one of these qualifying previous versions of Windows for them to work. In the United States, this offer expired in early December 2009. In October 2010, to commemorate the anniversary of Windows 7, Microsoft once again made Windows 7 Home Premium Family Pack available for a limited time, while supplies lasted.

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Wikipedia