I have Windows Vista installed on my HP Pavillion laptop. A few days ago, sound through my headphones stopped working. That is, sound is played fine through my computer, but now when I try to plug in headphones, it's as if the headphones are not there. My computer is completely ignoring that I have plugged in headphones. It keeps on playing music through the regular speakers. I've tried different headphones but nothing has changed. I've never had a problem with listening through headphones on my computer before, this only started happening within this last week. Is there anything I can do to? A setting I might've accidently changed? My one year warranty for this laptop is ending very soon...