i've had a similar intermittent problem with my dell laptop...vista seems to recognise my mic, but skype can't hear me...i found that i had to uninstall my sigmatel audio drivers, then re-installed them to get my mic to work properly..this happened twice to me for no apparent reason...both times fixed with the uninstall/re-install..i have a vlited install of vista, but i don't think this is the problem, as i only removed language, media centre and tablet stuff, and skype worked fine for the first couple of weeks