To fix the sound issues in Ubuntu 7.10, install linux-backports-modules and modify /etc/modprobe.d/alsa-base to include the setting for Intel HD Audio controller.
sudo aptitude install linux-backports-modules sudo gedit /etc/modprobe.d/alsa-base options snd-hda-intel model=dell-m42
After reboot you should be able to see all HD Audio components.
Raul A. Monsalve 