I'd been using mapsource and win XP on the macbook. I've switched to a netbook with win7 I downloaded mapsource but now it wont recognize the any devices(though mapsource does identify the flash drive on my android device), but no joy on either the 276c or the little Nuvi which I'm not trying to use now. What I want to do is load up a new 512mb chip for the 276c with the America NT mapset when I get to the USA. I don't have access to either my old computer or the original NT disc. I'm still registered with garmin and have the 276c serial number on file and the record of map purchase. I'm just not sure about how to go about being able to use the maps and/or whether gives gives free updates. From the website it seems garmin no longer supports the older map system. I'm sure others like me still use the 276c and have had to switch computers along the line. Garmin stuff can be very frustrating.