回复：用MSN MESSENGER和国内通话为什么听不到声音

If you have Intel network card, they can't hear you.
Solution:
"My network places" ->"View network connection"
Highlight the "Local Area Connection" get "Properties"
then uncheck "Qos Pocket Scheduler". Restart your computer after that.
The only problem is that you can download youe email at that setup. So you have to enable the "Qos Pocket Scheduler"and reboot your computer to get your email.