Window 8 laptop hp Humming sound

I hear a humming noise when the volume of keyboard f10 key reaches above 40

Also my sound does not carry to my TV via HDMI it used to be OK but I do not know what happened. I see the movies on the TV but no sound. Also when I attach a external speaker it sounds funny and not clear

Any one knows a remedy? May be in the control panel sound device I have to do something?

gerashi