I have a Lenovo ThinkPad Yoga with Windows 8.1. When an HDMI cable is plugged in, the sound is gone at first. When I set the speakers to default in the Sound menu, it comes back. However, only the laptop's built-in speakers work; when I try to plug headphones into the 3.5mm jack, there is no sound again. What else can I do except for changing the default sound device?