Flash plugin not producing sound

[Sian Mountbatten <poenikatu@fastmail.co.uk>]

Hello All

I have the flashplugin-nonfree package installed on my system (version 
1:2.8.3) so I can get the video clips working in my browser. 
Unfortunately, I am not getting any sound. The video clips without sound 
are not much use.

So what do I do to get sound working? I have two sound cards on my 
computer only one of which is connected to loudspeakers (the CA0106). 
The Intel sound card is part of my motherboard, but I do not have it 
connected to any speakers.

Any help would be appreciated.