It is a nagging problem in Linux which plagued me for quite some time. For example, if the Firefox window went to any page that contains needed sound(read flash) output, then immediately all external sound applications including amarok used to hand and also caused severe GDM freezes. It is fixed by doing the following: I reinstalled pulseaudio and libflashplugin support (which wasn't even installed): sudo apt-get install --reinstall pulseaudio libflashsupport and then changed everything to pulseaudio in "system->preferences->audio settings". This advice was posted here. Now amarok and flash run at the same time and everything seems to be fine. source : http://ubuntuforums.org/showthread.php?t=715486 See also http://kheyali.blogspot.com/2009/09/audio-problem-in-dell-laptop.html