Recently I had to install a new hard drive due to failure. This morning was the first time I have noticed that my mic doesn't work. I was running Dxdiag to create a file for a person to tell me why my keyboard goes out in the middle of a game when I noticed my mic doesn't work. How do I troubleshoot this? It is plugged in the same way as before and nothing else is different.

Look in control panel / sounds and audio devices , maby can troubelshoot from there

Double-click the volume control in the taskbar. click options, properties, scroll down and find microphone and make sure it's selected, uncheck mute. The mic is muted by default.