I'm a little confused. You mentioned that you had the headset paired to an adaptor, but then you said it was paired to your computer. If you have built in Bluetooth can you turn that off? Then plug the adaptor directly into your computer and then go into your sounds and audio devices and make sure that the adaptor you have is showing up under playback and recording. If the headset is paired to the adaptor, you should be able to see a solid blue light on the adaptor which means that the headset and the adaptor are paired with each other. Then if you click on the headset call control button you should see the adaptor start flashing. Once you have the adaptor flashing, try right clicking under playback on the adaptor and click test. See if you can hear your Windows tones through the headset. Then go to recording and right click the adaptor, go into properties and click "listen to this device" and then if you click the call control button on the headset to where you see the adaptor start flashing, talk into the microphone and see if you can hear yourself. If you still need assistance, you can contact the Technical Assistance Group at the link provided below:
http://www.plantronics.com/us/support/kb/ask.jsp#
