Many, many years ago, I bought a 3-cd set of Garmin MapSource TOPO maps (USA) for use with my GS64 unit. Years later (MapSource having died), I switched to BaseCamp and was able to get the TOPO maps to work with BaseCamp (i.e., to detailed view, rather than just to basic overview). I'm now in the process of setting things up on a brand new computer (HP desktop), but, for the life of me, I can't seem to install those maps in the BaseCamp on the new computer. Anybody have any ideas on how to accomplish this.