Upgrade version question

[JTsyo]

If you use a upgrade version of any MS OS on top of your current OS, will it free up the old OS key? Or does the upgraded version lock down both keys?

 

[armstrda]

Technically the upgrade license is a piggy back license on the old key, so in essence, that box will be using both keys.

 

[SonnyDaze]

I've been able to do a clean install with upgrade discs (XP/Vista) and only need the one key from the upgrade disc.

 

[Nothinman]

I've been able to do a clean install with upgrade discs (XP/Vista) and only need the one key from the upgrade disc.

But you can't legally use both keys. The whole reason that the upgrade license is cheaper is because you're not able to reuse the old key.