I want to be able to share videos with my net buddy - like from YouTube, for example.  My screen sharing works fine for video, but she cannot hear the audio.  I've tried searching for the answer, and I know it has something to do with system audio, but I've been unsuccessful in figuring it out.  I use a PC laptop, and typically do not use headphones for VCs.  Can someone provide step-by-step instructions, please?