Solly,
Bought my 301 nearly 3 weeks ago and I had same problem with PC not recognising presence of the device once connected. Garmin sent me a replacement disc to install SW etc, and that cured it..
Still have concerns over graphical display times not displaying same total as trip times, but no-one seems to have similar issue.
Ref : The SportTracks software, does anyone have problems with system retrieving map background ?? Mine's keep saying "connection to the map server is temporarily unavailable" ??