Cannot play sound: device being used by another application
Solution 1:
I had the same error on Windows 7 and managed to fix it by simply restarting the Windows Audio
service.
If it doesn't work, disable and re-enable the sound device using device manager.
Solution 2:
In the properties of your audio device, there should be a checkbox option labelled "Allow applications to take exclusive control of this device". IIRC it is enabled by default; disabling it and rebooting should resolve your issue.
Solution 3:
Best to combine both answers here.
As a resolution for now, execute in elevated prompt
net stop "AudioSrv" && net start "AudioSrv"
This restarts the Windows Audio Service. (Reboot will also work.)
To prevent future problems, disallow apps to get exclusive control to the device by going to sound -> (select device from list) -> properties -> advanced -> Allow applications to take exclusive control of this device .
Solution 4:
I had the same problem, and I solved it by installing an update (Chipset_Intel_Win_8) from the Asus website. I have an Asus RS51.