I’ve heard of a lot of people getting no sound out of Flash Player 9. Maybe retreat to 7 and see if you get sound back? Not sure how many sites you’ll be locked out of then for using the old version though.
This was taken from a different site:
Alright the problem is really the mapping of wavemapper in Windows registry as reported by one member of the forum. All you need to do is to open registry editor by going to Start menu, Run, typing regedit and then Enter. After that, in the registry editor, walk yourself through the tree in the left pane, till you reach
My Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32
And then on the right pane, right click and click on New, select String value, enter “wavemapper” (without quots of course), ENTER, type “msacm32.drv”, ENTER.
Close the editor. No need to restart. Video on Google and YouTube et al would work fine now.
Thanks to the member who pointed out the key. I just mentioned the procedure.
Have a nice day!