Seems that you can perform a clean install of Windows 7 – with an upgrade disk (read much cheaper here).
Normally, if you install with an upgrade disk, you cannot activate windows. The work around is to perform a clean install, ensure that there are no pending Windows Updates waiting to install (orange shield on restart icon), and make the following registry change:
HKLM/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/
Change MediaBootInstall from "1" to "0".
Open Regedit (Start, Type in Regedit and press enter)
Click “Yes” on the User Access Control
Navigate Regedit to: HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/
Right click on the MediaBootInstall key and choose Modify. Change the “1” to a “0”
Restart the computer, and you should be able to activate your “Clean” install of Windows 7!
Related posts:
Microsoft DPM
MicrosoftExchange
Nerd with a .45