A blog of the Freer Family's adventures and misadventures emigrating to Flinders Island, Tasmania, Australia, and settling there.
If the internet activation method doesn't work; use phone activation. It's a minute or two of reading numbers back and forth but should clear up any issues with a normal install not activating.
In my experience, if a legitimate and previously working installation of Windows starts saying that, it is usually a problem with the registry getting corrupted. Re-entering the correct key on your license generally solves that problem. Occasionally it is necessary to get rid of the corrupt registry file and restore it from a backup copy.