I've just been playing around with my internet phone but I'm having problems. If I do the Skype test call downstairs on the old PC it's crystal clear and works well. If I do it upstairs, though, the incoming quality is fine (i.e., the test caller, but when it reads back what I've said, the quality is appalling and barely understandable (if at all).

Does anyone have any idea what might be causing this problem? My PC upstairs is newer and better specced.

Cheers,

(Assuming you are using some kind of headset with 3.5mm jacks) have you plugged the mic jack in all the way, and not into your line-in socket?

The headset as such is an internet phone, with a USB connection.