Hi ...Windows XP with service pack 3 requires the Garmin usb driver you can down load it here :
Garmin Communicator Plugin
That is the official Garmin product that also ensures your Hand Held device has the latest software update. It is FREE of charge although they request you supply serial number of your device or it's unit I.D.
Serial N/O is behind the lid that holds the batteries.
Unit I.D. is Under the Menu option SYSTEM INFO
I shall PM you details of how to obtain Garmins latest version of their Mapsource program from their website. For your product.
I personally use OpenCPN and Mapsource under Windows XP Pro. Windows 7 and Ubunto Garmin does not offically support Ubunto (Unix O/S)
Kindest Regards Will