Have you tried removing the previous driver and installing the recommended one? Afterwards, you can try plugging in the device to another USB port.
Also, have you checked the Device Manager to see what com port is being used by the device?
One more thing, have you tested the ND-100 with another computer? What results did you get?
As for those unconceivable characters, can you perform a Cold Start in your device? First, you need to install this program, MiniCDU: (http://www.usglobalsat.com/store/download/650/minicdu.zip
). Download and extract the file. For more information on how to use this program, refer to this guide: http://www.usglobalsat.com/store/download/650/ug_nd100.pdf
Afterwards, please bring your computer outside. Please open up the MiniCDU program, plug in the device along with the cable, and press the Connect button. You'll see some data in the blank fields. Now, go to Command and select Cold Start. Check the Terminal window to see if you're getting the proper NMEA data. It takes about 45 seconds to get a fix.
Let me know how it goes.