I've been running Mint since 6. I wanted to upgrade to Mint 8, tired of waiting for KDE 8, so I did Gnome.
All went well so far. I installed the binary video. HOWEVER, like once before the headphone jack does not cut out the speakers or activate the headphones!
This was most embarrassing as I was doing it at Barnes and Noble, to check on-line on software (windows) I was buying for my Father-in-law.
Mint 8 was only 1 hour old, on my machine. I am going home at lunch to try some of the suggestions on the forum.
Audio: Card nVidia MCP67 High Definition Audio driver HDA Intel
Sound: Advanced Linux Sound Architecture Version 1.0.20
Control Panel show no headphone control!