You need to check the settings in both the system sounds (for the microphone) and also the program you are talking through. It may be a feature that your prior headset/mic didn't have the ability to use/access. It is really common for those programs to mute the microphone when going somewhere else, especially if that item is full screen and not actually directly in Windows (like so many games are). I would start with the system settings for the mic and the settings in each of the programs that you are having the muting. Also, if the headset came with its own installation cd (some do) then it would check its settings as well.