If I have audio problems I will run "alsaconf" as root, and then run my distro's sound configuration. Then I will make sure that sound isn't muted. Running alsaconf or updating a kernel or an update to alsa can cause sound to be muted.
If this doesn't work for you, you need to provide more information so users can help you. What computer model do you have? Run "lspci -v" and post the results.
Fedora 8 is old. If your computer is new, it may not recognize newer control chips. You might want to update to Fedora 11 to get a newer kernel and security updates. Pulse audio if it is used will work better as well.