Hello, Jennifer! (With your kind indulgence, I prefer informality.) I would try purging and then reinstalling Pulseaudio in the event that your /etc/pulse/default.pa file has somehow gotten mangled.
As root, "su -c" or using sudo: apt-get purge pulseaudio apt-get install pulseaudio Then, as much as you may dislike it, I would reboot to clear the memory and any stale files. I hope this helps! T.J.
