Hi Evan,
In addition to what Intel_JEspinosa has suggested, I've got two things to note:
1) There's some other "unknown device" listed in the Device Manager - do you know what's that? If not - try to uninstall it as well, together with the Gadget Serial one before trying to install the driver;
2) If the above doesn't work - you can right-click on the linux-cdc-acm.inf file in the hardware\arduino\x86\tools folder to install it manually - maybe then Windows will associate it with the device upon connection. This is rather weak option, but why not...
What I can see for sure is that your board is ok - because of the fact Windows detects the USB device and that's only possible if the board has booted its Linux properly.
