How Do I Register My Garmin C510?
Just a guess based on past experience with Garmin devices. Install any/all software that came with it, which should include MapSource. Then “sync” your c510 while this program is running and the first time it sees the device, it should go through the registration process.
Alternatively, go to Garmin’s web site and on the home page (www.garmin.com) select Support / Product Registration and you can walk through it that way.