Sounds like the sound card has gone belly-up then. Just 'cos the sound card is detected and the drivers work fine, doesn't mean it's still functioning.
Did you try downloading a linux livecd to test on your computer(playing some songs, etc.)? That way, you could see if the sound card is broken. You simply download the livecd, verify md5 checksum(to see if the download is complete), burn at 4x and boot from it. Nothing is installed and you're free to just wander around on the livecd.
Also, maybe reseat your card? Pull it out, and push it back firmly.
Last edited by Raito; 16/12/07 02:56 AM.