Hello, With the information you provided, I can give you some solutions that can solve it. '''1. Check volume mixer''' Make sure Firefox isn't muted in volume mixer. '''2. Reset sound defaults''' Go to volume mixer to reset sound defaults. '''3. Update audio drivers''' Sometimes audio drivers don't work, which causes audio incompatibility, such as Conexant audio. Open device manager, go to sound video and game controllers and update the drivers. (go to device manager by pressing Win key and typing device manager) '''4. Restart audiosrv''' Open task manager, find the audiosrv service, right click, then restart. '''5. Configure about:config''' In firefox, type about:config in the address bar and '''media.allow-audio-non-utility''' to false. After that, restart Firefox. '''6. Check autoplay settings''' Make sure autoplay is not set to "Block Audio and Video" in Firefox settings.