This confirms another theory, the live-CD you burned was corrupt, and that this somehow corrupted the kernel module in use, effectively removing sound from your system. This is the dmesg entry indicating that the CD is corrupt:
[ 39.403891] SQUASHFS error: squashfs_read_data failed to read block 0x25906a34 [ 39.403897] SQUASHFS error: Unable to read data cache entry [25906a34] [ 39.403899] SQUASHFS error: Unable to read page, block 25906a34, size 9d7d ** Changed in: alsa-driver (Ubuntu) Status: Confirmed => Invalid -- Soundcard not detected https://bugs.launchpad.net/bugs/551318 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs