I'm sorry for the continuing problems. I would suspect a rouge driver as the USB CDC used by the Logic Sniffer is a standard protocol supported directly by every operating system.
Windows should prompt you for a device driver (really just an INF file) the first time the hardware is connected. If not, you may have some old drivers in your system claiming all generic USB CDC devices if it says best available driver found. On windows 7 I am able to force it to use a specific driver and point at the .inf in the update package. Is that possible?
What driver does it say is currently used?
You can update the firmware by connecting the PGC and PGD pins of the ICSP header with a bit of wire, then press the reset button. The hardware will connect as a USB HID device (not COM port), and you can run the update package or use the various utilities included. Here's the officials and a list of user-created alternatives:http://dangerousprototypes.com/docs/Ope ... er#Updates