I have the HP Envy ultrabook 6t 1200 cto I just purchased it and have been using it for the past week, but the sound is constantly crackling and buzzing regardless of headphones or speakers, it buzzes when the laptop is plugged in. When it is unplugged it only crackles. Either way the sound is really messed up. Please shed some light on this, I have the warranty, but I have never returned anything so I would love it if anyone could tell me if it's fixable.