Loss of Sound - Help needed

I would be very grateful if someone could help to solve the following
problem with support by telephone. If anyone is willing and able to
supply such support, could they please let me know their availability
and how much they would charge per hour. Thanks very much.

(a) The sound on a desktop PC running Debian Jessie has stopped working - no
sound from any websites (e.g. BBC or YouTube) and trying to play a
standard sound file I have saved which is used to test the sound with
vlc gives:

Audio output failed:
The audio device “default” could not be used:
Device or resource busy.

and in the terminal window it says:

VLC media player 2.2.6 Umbrella (revision 2.2.6-0-g1aae78981c)
[00000000013f0608] pulse audio output error: PulseAudio server
connection failure: Connection refused
[0000000001318118] core libvlc: Running vlc with the default interface.
Use ‘cvlc’ to use vlc without interface.
[00000000013f0608] alsa audio output error: cannot open ALSA device
“default”: Device or resource busy
[00000000013f0608] core audio output error: module not functional
[00007fc2a8c02b08] core decoder error: failed to create audio output

(b) The sound was then suddenly regained.

(c) The sound has now been suddenly lost again.

(d) Loose wiring is not suspected.

(e) The only file in /etc/pulse is client.conf

(f) Running the pulseaudio command :-

% pulseaudio -k


pulseaudio: Command not found.

(g) files in .pulse are: