Hello Mavis. Although possibly not related to your problem, I will remind you that the version of Firefox you are using at the moment has been discontinued and is no longer supported. Furthermore, it has known bugs and security problems. I urge you to update to the latest version of Firefox, for maximum stability, performance, security and usability. You can get it for free, as always, at [http://www.getfirefox.com getfirefox.com]. As for your issue, see this support article. Hopefully it will be what you need: http://support.mozilla.com/en-US/kb/No+sound+in+Firefox