This morning I started up one install of my FSX to check on an aircraft installation (new A-26). After selecting the aircraft and finding it on the ramp engines running as usual, I had no sound, internal or external. The other installs of FSX are running properly. I compared the "modules" folder in the affected install with the same folder in one operating normally; both "GaugeSound.dll" files are the same. I tried aliasing the sound for the A-26 to another sound file I have for twin R-2800s, but this does not play, either. All sounds are inoperative on the one install. It looks like this is pointing toward a setting in either the "sound" folder for the sim, or in the sim's config file. Where should I be looking?