Walt,
Can you look at what VID/PID your Arduino Due shows up as when you connect it to one of your computers? Do this:
1. Plug in the Due using the Programming port.
2. Right click on the Windows icon on the bottom-left of the screen, and select Device Manager.
3. Under Ports (COM & LPT), select the Due board. I'm not sure, it will either show up as an Arduino or Bossa device.
4. Right click on that device, and click on Properties selection menu.
5. Click on the Details tab. Under Property drop down menu, select hardware IDs.
6. Let us know what the VID and PID is displayed. Due programming port should be: VID=2341 and PID=003D&REV_0001
Due Native port should be VID=2341, but PID should be 003e
(my "official" DUEs (all four) show these values. I'm looking for an ebay DUE that I have somewhere)
7. Note that the Bossa default VID/PID for most non-Arduino Atmel SAMx devices should be VID=03eb PID=6124
It could be that your Due has the wrong VID/PID combination, and therefore loading a Bossa driver instead of the Arduino one. I believe there is also an old Windows USB tool that showed VID/PID of connected USB devices, but I can't remember the name. Changing the Due's VID/PID will need to be researched some.
Please let us know the results of the above test.
Terry, N4TLF