[GTALUG] Ubuntu Studio: Sound not working in all applications

I have what I must describe as a strange sound problem under Linux Ubuntu Studio 14.x. The operating system sound is dead, so is sound which ought to come out of media players like VLC. Sound also fails to work in the browser. BUT, it DOES work perfectly under Audacity. I have tried to change the system settings to the same settings as Audacity, but I haven't been successful. THere was touted to be a window called "Sound Preferences", but when I clicked on the speaker icon to select "sound preferences" from the dropdown, the window that came up was "System settings", which only had icons for the printer, desktop and one other thing that had nothing to do with sound that I can't recall. Any ideas?