Hi Loay Alabdali,

I would suggest you to update the BIOS and audio driver on the system. Please enter your service tag # on the link below, select the OS, then download the BIOS from BIOS section and audio driver from audio section onto the system and install it.

http://dell.to/18r60nI

Also, please follow the steps below to run the diagnostics for the Microphone on the system.

1.       Open the link http://dell.to/14YjKb2

2.       Select ‘Hardware’ under ‘Choose a Diagnostic Type’.

3.       Select ‘Microphone’ under ‘Diagnostic Selector’.

4.       Click on ‘Run Diagnostics’ button.

5.       Let me know the results.