End-users also have to go through the hassle of backup all data files when clean install is required. The situation can also apply to user who installs Windows 7 Ultimate or Professional edition, but now wants to go legit by buying or being given a gift of Windows 7 Home Premium license. For example, users who installed Windows 7 Ultimate during beta or release candidate phase of Windows 7, but now acquire a Windows 7 Home Premium or Windows 7 Professional license. The refusal of Windows 7 to downgrade causes several groups of people some headache, especially when user doesn’t want to lose and wipe off existing programs installed. To install a new copy of Windows 7 Home Premium, click the Back button in the upper left-hand corner, and select “Custom (advanced)”. To save your files before installing Windows, back them up to an external location such as a CD, DVD, or external hard drive. You’ll need to reinstall any programs using the original installation discs or files. You can choose to install a new copy of Windows 7 Home Premium instead, but this is different from an upgrade, and does not keep your files, settings and programs. Windows 7 Ultimate cannot be upgraded to Windows 7 Home Premium. If user attempts to perform an in-place upgrade to downgrade to a lesser edition of Windows 7, an error similar to below will be displayed at compatibility report: Upgrade is only possible one-way from the lower edition to higher edition of Windows 7, and not the other way. Starter → Home Basic → Home Premium → Professional → Ultimate ( → Enterprise ) Windows 7 SKUs or editions have a hierarchy as below: For example, it’s impossible to downgrade from Windows 7 Ultimate to Windows 7 Professional, or from Windows 7 Professional to Windows 7 Home Premium or Home Basic. Windows 7 does not allow users to “downgrade” or convert from a more premium and more expensive edition to down-level, more basic and less expensive edition.