No Playback sound

I had no problems doing audio books last week. This week using same procedure, the is no audio playback. What setting do I need to check?

Check the obvious things first.
Check that everything is plugged in securely.
Try rebooting the computer.
If you’re using headphones, check the headphones plugged into something else (CD player, iPod, anything).
Check whether you are getting sound from other programs (Windows Media Player, YouTube,…)

If all that appears correct, check the settings in the device toolbar.
Set “host” to MME and ensure that the output device corresponds with the output device that you are using