A. There's no supported in-place upgrade from Windows 7 Professional to Windows 7 Enterprise, because Windows 7 Professional images are normally provided through retail or OEM channels. These images contain several editions of Windows 7 (Starter, Home Basic, Home Premium, Professional and Ultimate) in a single image, andWindows Anytime Upgrade lets you upgrade from one edition to another. Windows 7 Enterprise is a standalone edition, available only through volume licensing.
If you want to upgrade from Windows 7 Professional to Windows 7 Enterprise, you need to perform a clean installation. However, you can still maintain user settings by using the User State Migration Toolkit (USMT), and you can use technologies such as System Center Configuration Manager to re-deploy applications.