You will need to do a complete uninstall (KB #685), that requires you to delete the 777-300 entry in the registry. Then when you reinstall the 777-300, you will need to activate it again, you are then given the choice to do an Instant Online Activation (this computer must be connected to the internet) OR a Manual Offline Activation (on this computer using another computer connected to the internet). Select the latter AND you can use the same computer to do the Manual Offline Activation. I do it this way all the time now on my current computer (which does have internet access).

[edit]Added an image to show the entries in the Windows Registry that need to be deleted (see attached image).[/edit]

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