If you want to use Skype for Business/Lync to just listen to a training session or presentation on a newer computer, you might get an error saying Skype/Lync is unable to connect because no audio device could be found even though your computer may well have working audio and speakers.
The simplest fasted solution is to grab a pair of headphones and plug the headphone jack into your computers microphone jack. Doing so will fool Skype/Lync’s auto detect feature into believing that a mic and speakers are connected. The error will go away and you’ll be able to use your computer to listen to a training session. Unless you got headphones with a mic built in, the mic won’t work, but you’ll be able to join your conference/training and listen only.
Another solution is to fudge around with the registry per this TechNet article: http://blogs.technet.com/b/11/archive/2014/09/23/lync-2013-explained-no-audio-detected.aspx