Your motherboard's audio chip might have a headphone amplifier in it, and it's set for the wrong headphones.
Not too long ago, I upgraded from XP to Win7. Mostly this has been good, but it has introduced some sort of audio gremlin that's driving me fucking nuts. The info that seems immediately relevant: The ...
Not that I have a problem with Realtek... just interesting that they kind of ended up with a monopoly on sound, because the only alternative that I know about are add-in Creative products, which I ...