Hi Irene,
Where do you see this "microphone symbol"? do you see this as an error message on your computer? it actually depends on where you see this. Laptops with webcam normally has mic installed on it . So if you have problems recording or if you are talking to another person thru voip and you see this mic logo (with an X , ? or ! ) then it possibly have an issue on the computers mic device.

Hope this help.

Thanks

DENNIS