Whew!
This isn't Johnny but Dave, who jumped in this post when I also lost my sound in BB 2008.5 after recording an audio file
Thanks, Andrew, it worked - my sound is back! You're a genius. I was suspecting it must have something to do with the registry but didn't know where to look to fix the problem.
I was worried for a minute when I deleted all those registry entries and still wasn't getting any sound - until I remembered you have to reboot before registry changes take effect
Also after changing the registry, rebooting and starting up BB again, I had to hit the VSC DXI button and re-select VSC DXI under audio - then out came the sweet sounds of music.
Thanks again