Emmy’s Silent Computer
Wednesday, April 1st, 2009[Emmy] called tonight in a fright, because the speakers on her computer went silent. This meant that she could no longer hear the JAWS speech prompts, which in turn meant that she could no longer operate her computer at all.
We tried rebooting to no avail. I also had her verify that her powered speakers still had power. They did, because she could hear a low hum and hiss when she put her ears against them. Then I had her unplug the input audio cable from her computer and touch the tip of its jack. This produced popping sounds from the speakers, which suggested that the signal path from that point to the speakers was fine. So I logged in remotely and found that she had somehow checked the “Mute All” checkbox in the sound mixer program for her sound card. I unchecked this and the sound came back when we rebooted again.
I imagine this happened because she’d been wiping off her keyboard, and probably hit a random hot key combination that disabled her sound. So folks, the lesson here is to turn off your computer before you start dusting around the keyboard or mouse. Otherwise, you might cause a trouble that’s hard to track down.