Hi rizz538, you need to be more specific in explaining your problem. First of all, can you confirm that your Garmin model is GPS76? If so, looking at
the specs, apparently it does not accept map data except POI data. Furthermore, the connection interface is serial, not USB.
Or, maybe you're actually referring to
Garmin GPSMAP76? Well, this one still uses serial connection, but able to accept map data. Nevertheless, the built-in memory is only 8MB, so you need to use Mapsource with installed Malsingmaps map to select only some of the map tiles so that it would fit into the limited memory.
However, there is one problem though, current map version is compiled in a format not usable in these older Garmins, and the only working maps are the older v3.09 and any version prior to that. Please read this topic to learn how to acquire the map:
Maps woes...Having said that, if however your GPS comes with a USB interface, then maybe the model in question is
Garmin GPSMAP76C /
GPSMAP76CS. If so, you may download the USB driver from
here or
here. But not unlike the Garmin GPSMAP76, it's compatible only with the older v3.09 map.