You are using Garmin Express for the update - Correct?
Download Garmin Express to your computer first - either laptop or desktop
Then plug the GPS in using the USB cable - it doesn't have to be the one that came with the GPS
Express will recognize the GPS is plugged in
Click on one or two spots and a way it will go
***My last updates took over an hour per GPS
If your GPS is too old for Garmin Express to recognize it, it may be too old to be updated.
I did several GPS last week. If you still have problem, call Garmin, their phone help is very good. If the general people can't do it, they'll transfer you to the computer people. Call 800.800.1020
Bill