I am having the exact same problem as Aliza&Eliana. I have been using my GPS for about a year now with no problems, and then a couple of months ago it just would not connect to the computer. The GPS says it is connected but the device will not show on the computer.
I have tried multiple computers and downloaded the lastest PC version several times but the problem still persists. I hope it is not a fault with the GPS!
I will be grateful for any help or advise people can give!