I have NEVER installed a Garmin mapping product without at least 1-3 calls to tech support. Thank the Goddess that Garmin has good techs.
I could not get my GPSmap 276c, tried and true for 10 years, to work with my laptop.
Soooooo….through modern technology and eBay…
I bought a new/old Garmin GPSmap 478, which got me the latest maps for free as the free upgrade with a 478, WIN!
I sold the 276c on eBay for enough to pay for the 478, AND a XM weather satellite/radio antenna. The 478 can hold the whole country map installed, the 276c can only hold chunks, the 478 has XM radio and can display satellite weather maps, with the right antenna and the XM service.
This was about two weeks of work, but all is well.