Acer M5-481TG Service Manual page 202

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