Hi everyone, this is my first 'post' anywhere! My problem is that I've been using USB Headphones and now I can't get any sound from my speakers. The Realtek HD Sound Manager comes up blank, except for the three 'button' icons, speaker,headphone, headphone. All the messages tell me "no audio output device installed" My system is .... Medion Notebook running Vista. Has anyone any suggestions on how I can rectify this.