built in mics? I have not had this problem before, but today, when I switched my computer on, I found that the built in microphone was feeding sound directly back to the headphones. The only way I have found to stop this was to plug in a microphone with an on-off switch and set it to off. Disabling sound input devices does nothing, I have disabled all input and found that it had no effect, the sound was still feeding directly back. Is there any way to completely disable the built-in microphone temporarily? I am running Vista Home Premium and have tried the sound manager and audio devices menus to no avail, so any help would be greatly appreciated.