I bought a copy of Office 2010 on line and downloaded it, the vendor
supplied the product activation key by email. After installation I tried
on-line activation but it failed with an error "This product cannot be
activated as the product key is not valid" I complained to the vendor who
sent me another key. I cannot find any part of the activation process where
I have the chance to enter the new key. How do I replace the old key with
the new one?