-Deleting certain files like Options
-Setting Audio to Quad
-Clean Booting
-Repairing the games
-Re-installing the games
-Disabling audio devices
-Restarting
-Resetting folders
-Removing Mods
That is only off the top of my head.
I would recommend revisiting the 'disabling unnecessary audio devices' step since that's clearly the problem:
Open your windows control panel then "System" then "Device Manager":
Check your motherboard spec to determine which device is your primary on-board audio device and disable everything else.
In this example, only the "Realtek High Definition Audio" device should be enabled.
Edit: You've mentioned that you normally use headphones. If you're using a USB gaming headset or any USB audio device, search for the brand name in the audio device list such as "Kraken" or "Logitech" - you can leave the USB device enabled if it is the one you wish to use with the game however you'll have to re-enable your on-board devices if you intend to use your speakers.
I did as you said and nothing happened, as it works on all other games.
