Stopping PulseAudio is not recommended unless you know what you're doing. For example, your volume control application might stop working, and you can probably only have output from one application at a time.
How do you stop pulseaudio?
Press <Alt-F2> to bring up the "Run Application" dialog (Figure 1).
Figure 1. "Run Application dialog".
Type "gksudo gedit" in the dialog (Figure 2) and press the "Run" button.