See this to hopefully enable sound on your laptop:
I'm not sure how old that article is, but the correct package for the backported modules that you need to install for Ubuntu Karmic 9.10 is:
Then edit /etc/modprobe.d/alsa-base as it says in the article.
First, backup /etc/modprobe.d/alsa-base for safety before you edit it:
sudo cp /etc/modprobe.d/alsa-base /etc/modprobe.d/alsa-base.bak
Then add this line to the end of /etc/modprobe.d/alsa-base:
options snd-hda-intel model=acer
You may need to reboot to get the sound going. After you reboot open alsamixer
in the terminal and move all the volume levels all the way up using the arrows keys. Hit the Esc key twice to exit alsamixer.
Hope this helps.