i have the exact same problem with my hp mini.
i don't have enough experience with Windows 7 to know if it's that or something to do with netbooks? but as far as i can tell, Windows 7 seems to be doing nothing but causing problems where there weren't any before. I plugged in my speakers wanting ALL my sound to go through them...but it's registered my speakers as a headset and wants it to be my "default communication device", so only skype, etc sounds go through my speakers, everything else goes through the crap netbook speakers...i have no idea why. if anyone sees this and knows, really need your help!