Acer A315-53G Service Manual page 122

NOTE:
If Speakers is not shown, right-click on the Playback tab and select Show Disabled
Devices (clear by default).
Select Speakers and click Configure to start Speaker Setup. Follow the on-screen
7.
prompts to configure the speakers.
Remove any recently installed hardware or software.
8.
Restore system and file settings from a known good date using System Restore.
9.
If the issue is remains, repeat step 9, selecting an earlier time and date.
10.
Reinstall the Operating System.
11.
If the issue is still not resolved, refer to
12.
4-10
Online Support Information on page 8-2.
Troubleshooting