To register Magic Launch, simply enter your registration code exactly as in the email you received in the appropriate field of preference pane. The easiest way is to simply copy and paste it from the email you received to the registration window. If you are entering the information manually, make sure you enter both the registration code exactly as in the email since the information is case sensitive.
Click the Disable button at the top of the preference pane to uninstall the Magic Launch Agent application and link back your default applications. If you installed the preference pane for all users of this computer (by entering your administrator password), you should do this for all user accounts where settings have been changed.
Delete the preference pane: click the "Show All" button at the top of the window, then hold the Control key while clicking on Magic Launch. A contextual menu will appear with the option to remove Magic Launch.