If you have an orange speaker icon on your desktop (lower right hand corner), right-click on it, then click on audio devices, then click on the "recording" tab, then select your laptop's microphone. Then, click properties, then the "listen" tab, then make sure that "listen to this device" is not enabled. If that doesn't work, then make sure that there's no other mics in the list under the recording tab. Either that, or you're using a mac, or a windows computer that doesn't use realtek audio, and I wouldn't be able to help you in that case. You could also try opening task manager (or the mac equivalent?) and closing any application you know uses the microphone.