In truth, I bought this a few months ago and upgraded it then. I never did find a solution despite (re)installing countless drivers. My Compute Stick has been collecting dust since, and I still feel like it's been a waste of money.
Could somebody point me towards a solution?
First of all, go to Intel's download center (http://downloadcenter.intel.com) and download and then install the latest available Audio and HD Graphics drivers for your NUC. If problems persist - and you are using HDMI or Display Port (DP) audio (i.e. audio output through TV or HD Receiver), the next thing to be looked at is the cables that you are using.