I am using Windows 7 operationg system on a Pavilion dv9607 notebook. I plugged my earphones in and listened to videos, left them plugged up and muted my sound system. A day later, I listened to some videos witht he headphones so I unmuted the sound and watched a few, then muted it again, leaving th eearphones plugged in. I came back to a video and tried to unmute it and got a window telling me it was trying to detect the problem with my sound system, and it will no longer let me unmute it. What is going on and how do I fix it?