To be honest. The sound has been working all the time. The problem was that the volume of the sound configuration files is too low. So I change the sound volume a little higher and everything works to perfection. No mdll, no nothing. Just change the volume to a higher settings.

For example:

microsoft fight simulator x / Captain_sim / 757

[Common]
Refresh.Time=10
Sound.Directory=Captain_Sim\757\sound
SoundOffWhenSimIsSlew=1     <==== 1 must be change to 0
SoundOffWhenSimIsPaused=1
SoundOffWhenSimDialogIsOpen=1
SoundOffWhenSimSoundIsOff=1


then scroll down.......


; ----------- APU------------------

[Sound.0]
File=apu_start.wav
Id=10000
Volume=0.2  <=== Change 0.2 to 1000

[Sound.1]
File=apu_idle.wav
Id=10001
Volume=0.2    <=== Change 0.2 to 1000

[Sound.2]
File=apu_stop.wav
Id=10002
Volume=0.2 <=== Change 0.2 to 1000


You must change all of the volume numbers to 1000 to hear all the sound. Remember the higher the number the louder. You can change the numbers to your liking. The "conditioning" file for the air conditioning is loo low. Try changing the file for a higer, better one you can find maybe at avsim or so. Hope it help you.

Dominicana1930