I hear a noise when the microphone volume is high on lappy

[anonymous_20]

i am using a dell inspiron laptop.bought the lappy 2 years back.last week i kept it open for two days..from then i hear a strange sound from it.itt vanishes when i reduce the microphone(Hd) volumeunder volume settings

 

[popatim]

mic is normally muted, go ahead and check the mute box and silence it.

 

[anonymous_20]

can u explain how to do it clearly..i generally mute the system sounds to get rid of that sound