Hi,
Please download Audio driver from the following link (for both 32bit & 64bit) and re-install on your machine:
By the way, the model of your machine is: "HP Pavilion g6-1220sa", the following link shows its specs:
http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&dlc=en&docname=c03072277
Regards.