You should only be prompted to enter an Installation Key the first time you run the EIOBoard Intranet Installer on your server. Scenarios where this would occur include a brand new customer installing for the first time, an existing customer that is moving EIOBoard to a different server, or an old EIOBoard customer that is on version 5 or earlier that has never ran the EIOBoard Intranet Installer before. In any other scenario, you should not be prompted to enter an Installation Key. If EIOBoard is already installed, the EIOBoard Intranet Installer will recognize the existing installation and do an in-place upgrade, making a backup in the process, and also keeping all your existing data (users, settings, status history, etc.) intact.
If you have previously installed the EIOBoard Intranet Installer on a server you are trying to upgrade and it is asking you for an Installation Key, you will need to contact Savance. We can do a GoToMeeting to your server and work through the issue with you. Most likely something is corrupt with the original installation and Savance can help you to quickly rectify this problem and not lose any of your data. The normal process is to manually backup your database and files, take note of your website configuration in IIS, uninstall your existing version of EIOBoard Server, then do a fresh install of the latest version and reference your existing database backup.
If you are not upgrading and instead moving to a new server, you should read over the knowledgebase article that is most applicable:
Moving EIOBoard to a Different Server but keeping SQL separate