Herman
Taken from the Garmin FAG page:
1. Go to the Satellite status page and press the ‘Menu’ button
2. Select “New Location”
3. Select “Automatic”
4. Let the GPS acquire for a bout 15 minutes, stationary with a clear sky.
I found the above before finding you had resolved the problem.
At times I treat a gps unit, the same as I treat a home computer. If the home computer glitches I will shut it down and restart it. I do the same thing with a gps unit. It seems to correct about 99% of the problems. In effect you reset you unit when you shut it down and restarted it.
Before doing an update on my gps units I connect to Maps Source and save my waypoints, tracks, and routes. A couple of times I have had the waypoints, tracks, and routes showing on the desk top from one gps unit, and downloaded the data from a second unit to the desk top. It requires a little housekeeping because of waypoints with duplicate names, but the new waypoints are now added to a master file along with the old.
I also maintain a downloaded update in a Folder for my gps units incase I encounter a problem it gives me a starting point.