Just recently, my Sennheiser PC360's microphone stopped working. Yesterday Night, it was working 100% fine. Muting correctly, un-muting, volume boosting, etc. I woke up this morning, and got into a skype call (After not changing a single setting on my computer), and it wasn't working. I tried mumble, and it didn't work there either. After that, I checked my sound devices and found out it was plugged in, but not responding to my voice. I unplugged the headset, and it correctly showed that it was unplugged. So, a quick run-down:

• Sennheiser PC360 Headset suddenly stops working after a few hours of sleep.
• Software is up to date
• I can hear the mute sound when I raise and lower the microphone arm
• Windows Sound Device Manager shows that it is plugged in
• Unplugging the headset correctly shows it is unplugged
• Windows Sound Device Manager shows that the microphone isn't receiving any input