Hi nayaa,
Welcome to the HPCommunity, I hope you enjoy your experience! To help you get the most out of the HP Forums I would like to direct your attention to the HP Forums Guide First Time Here? Learn How to Post and More.
I understand that you are having a problem with built in mic on your Pavilion. Here is a link on setting default audio and recording device. The first part of the link is for setting default audio device but if you scroll down it will show you how to set the default recording device. If that doesn't work then reply back with your product number and we will look at installing a driver.
Thank you,