If you install the upgrade disk on a NEW hard drive it will not work..According to Microsoft Website..(Microsoft Store)
If you have Windows Vista, you can purchase Windows 7 Upgrade versions. You can do a clean install (back up your files, clean install, and reinstall your applications) or an in -place upgrade (Windows 7 installs over Windows Vista).
You need to have Windows Vista or XP in order to an upgrade..
You can do a clean install over Vista and XP.. BUT YOU HAVE TO HAVE THE OS ON YOUR HARD DRIVE..
If you have a new hard drive with nothing on it you will need the FULL
Version of Windows 7..
Hope this Helps...