I use Skype frequently for voip. After I reboot, and for an indefinite time after, everything works fine. But eventually my microphone (Dell built-in) stops working. The party at the other end no longer hears me. It's not just Skype. Windows Sound Recorder doesn't pick up anything. Neither does Audacity. My thinking is that some app is grabbing the device and not releasing it. Is there any way of determining if this is the case? If so, is there a way to determine what app is responsible?