Just another thought, i just downloaded Yahoo Messenger plugged in my Mic and i put on some music, and when i logged in entered the chatroom i came up with a error, saying that my Audio device could not be detected..
So i was wondering when you log in are you listening to music? Got a game running in the BackGround?
I say this because if you do then your Sound Card is being used to run something else, therefore your MicroPhone won't work.
And it will do the same thing if you have some type of music/ Voice recording program open as well.
So this might just be the problem..

anyhow if that aint the reason then i'll go back to the drawing board and perform some more test's..

cheers
.:f2b:.