Was just googling for Windows 7 upgrade activation and found this hopeful tidbit:
"As Oct. 22 approaches, I bet you've been wondering: If I buy the cheaper, upgrade version of Windows 7, am I going to have to reinstall my old operating system before I install this one?
So far, there's been no clear guidance on this from Microsoft - until now. I've been asking a spokesman for the company about this for about a month, and he's finally been able to offer an answer.
It's an interesting one.
If you are running the Windows 7 Release Candidate, and you have activated it, you will not need to reinstall an older version of Windows before using an Windows 7 upgrade disk.
However, you will not be able to do an upgrade installation, in which your existing programs and data are left in place. Instead, you'll have to do what Microsoft calls a custom installation. This is essentially a clean install, but your existing operating system, programs and data are squirreled away in a folder labeled WINDOWS.OLD. You end up with a fresh Windows 7 setup, but you can access that folder to get to any needed data. (Sorry, the programs in there won't work - you'll need to reinstall them.)
That's good news for folks who worried they'd have to do two operating system installations to get the final version of Windows 7 on their PCs.
But there's a catch. If for some reason you later need to reinstall the finished version of Windows 7 from scratch using the upgrade copy you bought, you'll first need to install and activate Windows XP or Vista.
This is different from Windows Vista's installation procedure. Vista would let you install an older Windows OS, skip activation, and then install with an upgrade version. You can no longer skip activation when installing Windows 7 via an upgrade disk.
In other words, it's all about activation. The Windows 7 upgrade disk will need to see a valid activation - and that can include an activated copy of the release candidate - before it will install the operating system.
This should make life somewhat easier for those running the Windows 7 Release Candidate - so long as they don't have to do a reinstall later.
http://blogs.chron.com/techblo...estion_gets_an_an.html