Most users who visit our website are running at least one version of the Windows 7 operating system on their computer systems. It is likely that the majority runs Windows 7 RC, the last official public release of the operating system. With the release of Windows 7 only a few months away it is time to find out how to upgrade the Windows 7 RC (and other post-beta builds of Windows 7) to the final version. Not everyone wants to upgrade and that is perfectly fine as well. A clean install makes sure that no garbage is taken over from previous installations.
Some users still might want to upgrade the RC to the final release version as they might be running Windows 7 already on their main computer system. Dwight Silverman recently confirmed that it is indeed possible to upgrade the Windows 7 Release Candidate version with Windows 7 Final. Probably even more interesting is the fact that upgrade versions of the retail version of Windows 7 can be used to upgrade the release candidate to the full build.
The data on the other hand will not be taken over. The installation will move all data to a folder called windows.old from where the files are accessible. It is not possible to run programs from there unless they are portable though. It should also be noted that it is not possible to reinstall unless a copy of Windows XP or Windows Vista is available that has been installed on the computer system.
To sum it up: If you are running the Windows 7 RC you can buy a Windows 7 Upgrade to install Windows 7 final on your computer system without needing Windows XP or Windows Vista during the first installation.