Click Start and then type Sound in the Start Search text area.
Click Sound in the Control Panel section listed above.
Click the Playback tab and click on the picture with a green check mark next to it (should be the default device) so it is highlighted.
Click on the Properties button.
Click on the Advanced tab.
Uncheck the box next to this line: "Allow applications to take exclusive control of this device."
If issue still persists I would recommend you to update the sound card drivers and implement other ideas shown in Acer Aspire E1-531 Good Luck.