Hi [NAME] is seems that the IDT 92HDxxx HD Audio Driver has been corrupted. Please open Device Manager and open Audio Driver to see if it is working properly. Installing IDT 92HDxxx HD Audio Driver | Driver Details | Dell US again, followed by Restart (not Shut Down) will hopefully fix sound mute problem. 
Hello Dell support team, i am sufforing for mute issue in my laptop. its one pop up cam at left side on screen and showing mute, and am trying to inscresing the volume then it immediately scrol down to mute. so please resolve this issue ASAP. Thankyou, Rasheed mohd. [IMAGE][IMAGE]  
Audio mute issue