This morning I installed openSuse 12.2 in one of 3 OS partitions. Grub2 of OpenSuse catched my Mint 12 entry... and I can boot it ok. When booting Mint 12, something happened with sound: when the led of the HD lights up because of HD operation... a wired/noisy sound is heard in speakers.
I re-installed pulseaudio... and the problem remains. I don't know if this might be a result of openSuse install ... or its just mere coincidence. I have been working with Mint 12 for a while and sound has been perfect, 'til now.