As far as I know, with Windows 7 you could install upgrade versions without upgrading anything, as long as you didn't activate it originally. But it looks like the hack for Windows 7, where you install without activating and then later activate doesn't work (http://www.pcauthority.com.au/News/320816,boxed-copies-of-windows-8-pro-do-not-work-for-clean-installs.aspx)