I have a Sennheiser PC 151 and its microphone has recently stopped working. I have Windows 7. According to troubleshooting and the properties setting of the sound menu there isn't a problem, but as you can see in the screencap (by the empty bars to the right) the microphone is receiving no sound. Almost all the resolved issues with PC 151 or just a mic on Windows in general that I found via google seemed to involve Windows not detecting the mike, which is not the case here. Any ideas?