Sound in Firefox

[Goh Lip]

I am not getting any sound in Firefox, say youtube after reinstalling 
karmic alpha3. Video ok. (External) kaffeine sound/video ok. Any ideas?

Some background info....

o before reinstallation, no sound problem. (reinstall to clean up some 
loose ends, like manual mounting, fstab, etc which was inherited from 
Jaunty bad conversion to kde 4.3; generally nothing major)

o reread and followed Myriam's earlier email, I think on Intrepid, ie.,
remove-purge pulseaudio, remove ~/.kde/shared/phonon<sumthing>rc, 
restart. No difference, still no sound. (I did not have this problem 
then or needed to use her instructions). Reinstalled pulseaudio.

o have softlinked .mozilla (and others) from Hardy to Karmic.
Shouldn't be an issue, right? Definitely didn't softlinked .kde.

o plays well (sound & video) on firefox in Hardy though. (Same 
.mozilla). But hardy flash is v9 and Karmic v10. Cannot see why this 
should be an issue. Prior to reinstallation is also v10.

o Hardy 64   2.6.24-24, kde 3.5.10
   Karmic64   2.6.31-4   kde 4.3 rc3

Will appreciate any input.

Thanks & Regards,
Goh Lip