Laptop No Sound

Hi! I have an ASUS S550C laptop 64bit Windows 8 and recently there is no sound from the speakers. Despite the speaker icon in the taskbar is functioning, whenever I play music, videos or anything that has a sound, it's like on mute. Whenever I test it, it says "The device is being used by another application. Please close any devices that are playing audio using this device and then try again." despite having no running application. I tried unchecking exclusive mode from the properties and it worked for a while. Any help would be much appreciated.