It is a keyboard. It does not need drivers or anything, so if hitting buttons does not register keystrokes in anything (text file, google search field, or even their test utility) then chances are it is the board that went bad. Hopefully not......Whatever it is the signs point to the Tankstick and not software like Mame or Launchbox. I use one in my main cabinet, it still has a regular keyboard and a mini bluetooth keyboard connected to it and the Tankstick does not care. It works. I replaced a board that went bad on mine last summer so it is not unheard of.
Also if plugging it into another USB port or even another pc still does not yield working buttons I would suggest calling their support line. Not much more troubleshooting from here can be done I am afraid.