Don't know if you've tried this yet, the other possibility is the DRIVER. If you plugged it in and let windows pick the driver invarably it picks the wrong one. Check your c: drive for Garmin usb_drivers, There is an install_usb.txt file the contents of which are...
Installation of Garmin USB Device Drivers
1. Connect the USB connector on the end of your device to the
USB port on your computer. Any free USB port on your computer
will work. The computer does not need to be turned off when connecting
or disconnecting your device.
2. The computer will recognize your device as a USB device and open the
Add New Hardware Wizard and search for the driver.
Click on "Next". If, for some reason, the Wizard does not run
automatically, click the Start button and select "Settings" and then
"Control Panel". Double click on the "Add New Hardware" icon.
3. The next screen will ask you if you want to search for the best
driver for your device or if you want to display a list to choose
from. Select "Search for the best driver for your device" and
click on "Next".
4. The next screen will display a list of locations to search for the
new driver. Select "Specify Location" from the list and click
on "Next". Make certain all other boxes remain unchecked.
5. The next screen will prompt you to enter the location of the driver.
Enter the location (either the CD or the folder where the driver was
saved) and Click "OK".
6. The Wizard will search for the driver and then display a window to
tell you it is ready to install. Click on "Next". You may see a
"Copying Files..." screen which tells you the file cannot be found.
Choose the folder that contains the driver files and try copying again.
Click "OK" to continue.
7. When installation is complete a window will display that shows the
device name and states that driver installation is finished.
Click on "Finish".
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