if you go to your sound and audio devices in your control panel and go to to the voice tab at the top you should see volume button under voice recording. click on it and make sure you check the box to select your mic.
Click to view attachment also make sure you have your mic muted under the volume tab-device volume-advanced...
Click to view attachment a good place to test and see if your mic is working is if you go to start at the bottom of your screen-all programs-accessories-entertainment-and sound recorder.
Click to view attachment try that and get back to us!