If you jumped onto Microsoft Windows 7 pre-release version (Beta or RC) you can't upgrade to the final RTM version and need to do an clean install loosing all your settings and installed application as Windows 7 setup won't let you upgrade from a pre-release version to final build displaying error as below.
Luckily there is a simple config-file hack which allows you to do an in-place upgrade from Windows 7 pre-release to final version keeping your files, settings and applications intact.
Bypassing Windows 7 RTM setup pre-release check and update :
- Download the Windows 7 RTM ISO and extract the contents to a folder.
- Now navigate to sources directory in extracted folder and open cversion.ini in notepad for editing, also don't forget to remove the read-only flag from the file.
- Now change MinClient value in this file to 7000 or lower and save it as shown below.
- Launch the setup and if will allow you to upgrade.