You can create a backup of your maps with JaVaWa GMTK and restore these (e.g. on another computer) including unlock codes. Re-installing maps is unnecessary.
Migration of your Garmin maps from and old computer to a new one is straightforward with this application.
Do you want to use your maps on a second computer like a laptop or netbook? JaVaWa GMTK takes care of it.