No sound at all on openSUSE 12.2

I have the problem with sound on openSUSE 12.2 (kernel 3.4.11-2.16) since recently. The system is updated from official repository+Pacman regularly. A couple of days ago, I noticed that sound works just for less than a minute in Skype (I thought that Skype is to blame). After reboot the sound works in all applications just for short, and endless attempts to resolve the problem haven’t helped (the sound reappears only after reboot). The problem is the same for all applications (Kaffeine, Skype, VLC player, Chrome…). Sometimes, bar in pavucontrol reacts, but still without sound. I tried killing the pulseaudio, it restarts but nothing happens. I also tired to reinstall all the pulseaudio libraries.