Paul Thurott and friend have worked out how to do a clean Windows 7 installation whilst only using the Windows 7 upgrade disc.
The instructions are as follows:
- Perform a clean installation using the Upgrade disc.
- Install all pending Windows Updates.
- Open regedit.exe from the Start Menu.
- Navigate to HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/
- Change MediaBootInstall from ‘1’ to ‘0’.
- Open the Start Menu again and type ‘cmd’ — use ctrl+shift+enter to run it as an elevated-permissions user.
- Finally, type slmgr /rearm — and press enter.
You can now reboot and activate Windows 7 by running the Activate Windows utility, type in your product key and it should now work.