how to detect if mouse is not on stage when the stage is fullscreen

I have an exe file that opens fullscreen. When I press button on that exe file opens another exe file but the first one stays in the back. Both have background music, so when the other one opens you hear both background musics.
I made an function when you press a button that volume of the first exe file sets to 0
on(release){
      fscommand("exec", "newexe.exe");
      soundVolume=0;      
}
and on main actionscript I put this code, so when someone closes the second exe and returnes to the first one and makes first mouse move that sound again apears
onMouseMove = function () {
      soundVolume=25;
};

But :)
if someone clikcs a button that opens new exe and also makes a quick move with mouse before the second exe opens the sound will play anyway.
Please help and thank you for any suggestions?Start Free Trial