(If you still don't see Stereo Mix, try to plug in a mic and enable it)
Start > Control Panel > Sound > Recording tab > If you don't see Stereo Mix, right click and select Show Disabled Devices > Enable Stereo Mix
On Steam right click StarWars Battlefront 2 > Properties > Set launch options If you have a black screen, try this: - (screenshot) Set resolution to MAX and make sure anti-aliasing is off