I successfully upgraded the OS on my Viliv X70 from Windows 7 RC (Release Candidate) to Windows 7 RTM (Released to Manufacturing). The magic word is upgraded, as opposed to a clean install. By upgrading, I don’t have to reinstall my applications.
Of course, it’s never easy. There are two hurdles to overcome. However, in the spirit of Martin Luther King, “We shall overcome.”
The Windows 7 RC edition is Ultimate. The installation checks if your RTM edition also is Ultimate. If yours isn’t (mine is Professional), installation stops.
How to Upgrade Windows 7 RC Ultimate to RTM Enterprise gave me the idea of how to solve this. My edition is Professional, not Enterprise, but the concept is the same. Start the Registry Editor (regedit). Go to HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version. Replace the word “Ultimate” with “Professional” in ProductName and EditionID. Now my RTM and RC editions match, as far as the installation program is concerned.
The installation also checks whether your current Windows 7 version is pre-RTM by checking if the version number is lower than RTM’s 7233. If it is, and RC is at 7100, installation stops. However, How to Upgrade the Windows 7 RC to RTM (Final Release) (and this older blog entry) explains how to solve this issue by editing a file in the install to accept a minimum current version of, say, 7000, low enough for RC to qualify. The process requires copying files from your DVD to your hard drive, but is explained well in the articles and isn’t difficult.
These two hacks seem perfectly legal. You still need a legal copy of Windows 7 RTM, and your legal copy entitles you to an upgraded or clean install of the edition you purchased.
Of course, the usual caveats. No guaranties. Your mileage may vary. Back up everything. Make sure you know what you’re doing. Follow directions. Fully charge your battery + plug the X70 into external electric power. Wear clean underwear in case there’s an accident.