Restarting ALSA is extremely simple. Follow these steps:
$ /etc/init.d/alsa-utils stop $ alsa force-reload $/etc/init.d/alsa-utils start
or sudo /etc/init.d/alsa-utils restart
If you get a dialog box asking if you would like to reload something that was shut down with ALSA, select "yes." Close the terminal now as you don't want to stay root.
You are all finished now. Wasn't that simple.
If that didn't fix your problem, you might be using a different sound driver (Like OSS or PulseAudio). Try changing your sound driver in your OS sound settings and seeing if another driver works instead. Also, make sure in your volume control options that both your Master and any other options (Like PCM) are all on and high.