From a technical standpoint, an OEM version of Windows 7 is roughly identical to a Full version of Windows 7. The discs are available in 32-bit or 64-bit versions, for all of the mainstream Windows 7 versions. However, these discs are only supposed to be used to clean install the operating system, and once that OS is installed and activated on a particular PC, it cannot be deactivated and moved to a new PC. The OEM is required to provide Windows 7 support to the user that buys the PC on which it is installed. The OEM must also stick the included Certificate of Authenticity (included with the OEM Windows 7 packaging) somewhere visible on the PC they are selling to an end user.