Some Acer models include audio settings within Acer Quick Access (look for “Audio Boost” or “Mute Button Configuration”). Update this utility from Acer’s site.
Once you get your sound back, you need to lock it in. acer sound drivers
Before downloading anything, you need to know exactly which driver you need. Follow these steps: Some Acer models include audio settings within Acer
Many Acer users cannot access the Realtek Audio Console, which controls volume levels and speaker configuration. acer sound drivers
Do not just click "Update Driver." Here is the professional fix: