How can I see registry entries

If you want to check whether an entry to registry was sucessfull or if you want to check which product IDs are taken already you have to look in the registry.
To do that you click on the start button and choose 'Run…' a small window will open and there you enter 'regedit' and press enter.

After that the registry editor will open and you can navigate to your Mapsource products and maps which you should find here: HKEY_LOCAL_MACHINE\SOFTWARE\Garmin\MapSource