It's more than likely a driver issue. Linux has come a long way in its progression with drivers, unfortunatly, it is not perfect yet.
You may also try the sound properties.
List the specs of your PC and we may be able to help you more.
__________________
<code>
(\ /) This is Bunny. Add him to your signature
(O.o) to help him achieve <a href=\"http://carboxymoron.com/sigbunny/\" title=\"the signature bunny\">world domination</a>.
(> <)
</code>
<code>Shakie<br>Smodministrator<br>
\"If I don\'t step over the line every now-and-then, how will I know where it is?\"</code>