Windows 7 - Product Key Is Not Valid

When reinstalling W7 (after all, it is Christmas) I was advised that my product key was not valid. Me... Use an invalid product key... Never! And besides, this is a retail upgrade pack.

So what's wrong?

Turns out this is a known issue where under a normal reinstall, your product key will be rejected. At issue is the fact that his is an upgrade disk rather than a "full version". It assumes you have an existing OS. The good news is there is a Microsoft work around.

http://windows.microsoft.com/en-US/windows7/Windows-7-activation-error-invalid-product-key

To save you the effort of reading their propaganda:

1. Select Custom Install.
2. Highlight the target disk.
3. Click Advanced.
4. Click Format.

After the second install completes, you will be able to use your product key.