Just had a lovely couple of hours tracing a problem where firefox would hang
very quickly after start-up; even right clicking on a menu item made it
hang. I had missed the fact that the speaker symbol was absent in the task
bar (volume on my speakers was off anyway), but finally managed to trace the
issue to pulseaudio. Unplugging my webcam and usb headphones before booting
solves the issue.
Found a similar statement on an ubuntu list--but hope this is helpful to
someone searching for this issue.
Niels