Possible Duplicate:
Windows 8 upgrade
If I purchase the Windows 8 Pro copy via the Windows 8 offer that's currently running until Jan 2013, do I have to install it on a PC having an existing installation of an eligible copy of Windows 7, or will it allow upgrading from a regular blank hard drive?
Also in the future if I need to reformat my PC, will I have to first install Windows 7, and then upgrade to Windows 8?