Follow the steps below to switch your audio from your TV to your Speakers or Headset.
Click the small speaker icon next to the clock on your Windows task-bar.
Select the small up arrow ^ in the upper right-hand corner.
Select your output of choice from the list that appears.
It will usually be AUX or Speakers for the sound system. Just try each of them till you get the correct one and take note for the future.
Let us know if this doesn't work and we can come by and check it out.