Using headphone as a microphone
Did you know that you can quickly turn your headphone into a microphone? And there's no rocket science or audio engineering involved. All you need to do is plug-in your headphone into the standard microphone port on your computer, and turn on any audio recording software. I remember having tried it years ago using my Windows Vista machine and Audacity audio recording software. While the quality of the sound isn't very great, it does the job. Imagine a case where you want to make a Skype call through your PC and you don't have a mic (and your computer doesn't have an inbuilt one; highly unlikely these days).
All you will have to do is simply put the headphone jack into the microphone jack and start speaking into the earphones as if it's a mic. Should solve the problem temporarily. I found it surprising that not many people know this trick! But you do, now!
This is possible because the working principle of both headphone and microphone is the same. The vibrations are converted into electrical in a microphone energy and vice-versa in a headphone. I haven't tried the trick in recent times, but if you have a separate audio/mic port on your system, you should give it a try. Do let me know if it works.
Also check if you can get any sound output if you plug-in your microphone in the headphone jack. Don't blame me if you damage anything in the process. Should be worth the try and the chances of damage are very minimum. π