When I installed Mint 7 on my newer Acer laptop with
Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 04)
I had no sound.
Upgrading Alsa fixed it for me.
The Alsa Upgrade Script is located at the bottom of the first post
* download the script
* cd <your-download-dir>
* tar xvf AlsaUpgrade-version.tar
* sudo ./AlsaUpgrade-version.sh
where "version" is the latest version that you download