is your pc pingable from the internet? what hardware do you use? on the other side, does the user use a headset for both mic and speaker? most of the time it's a hardware problem, but sometimes it's the network settings. you have to check both sides, some simple logic are: if you can let some other people hear you, then it's most likely not your side's problem if the other side can hear other people, it's most likely not the other side's problem if you have more than one computer you can try tes