Can I Downgrade From Windows 7 To Vista Home Premium Using An Upgrade Home Premium Disk?
I am going to buy a new hard drive for my laptop and I’m going to clean install Windows 7 onto it. I am wondering though if I can use a vista home premium upgrade disk or if I would have to do a clean install of vista due to the fact Microsoft would consider it a downgrade.
No, you’d need a full version because it’s a downgrade. The upgrade version of Vista requires a previous version of Windows to be installed before it will upgrade.
The upgrade discs need to see a prior genuine version of Windows to work, and it needs to be an earlier build.
If you get Vista onto the drive first and activate it, that will work for upgrading to Windows 7. You shouldn’t be able to “downgrade” moving from Windows 7 to Vista, however.
You would have to install the Vista operating system first, the Windows 7 upgrade will look for prior versions of windows to authenticate with before installing.