Sometimes one of the emulators we use, Retroarch, will not play audio for some games. If you encounter this, follow these steps:

In AGS, open one of the games you are having this issue with
To access the Retroarch menu, press R3 (press down on the right joystick on your controller), or if you have a keyboard connected, press F1 on your keyboard
A menu should appear, press the "back" button to open the side menu
Select "Settings"
Select Drivers
Select Audio
Your default audio driver should be xaudio, change this to either openal or dsound
Return to the Main menu
Quit
Relaunch the game
Audio should be fixed!