fs9 lost all sound

I'm using FS9 on a windows Vista system. everything was working fine until I downloaded and installed the Ifly 747-400 and service pack3. after the install I lost all the sounds from FS. I don't even have the clicking sound while selecting menu items on the start up page.(weather, airports, time of day ect.) All other sounds on my computer are fine. I uninstalled the Ifly plane and the sounds didn't come back. Has anybody had this happen before? Any ideas how to fix this short of reinstalling FS. (I have over 200 aircraft and would hate to have to reinstall them all). I have been using this set up over 3 years now with very few problems. I looked through a bunch of this forum for clues but didn't find anything. If this has already been covered somewhere please point me to the thread.Any help you can give would be great, and thank you in advance.......