Working with 3rd grade students podcasting. Ran into an issue where their audio track would be muted and nothing recorded (straight line), previous sound recording fine and no idea what could have caused the muted recording. This happened to about 1/3 of the computers. Is there a shortcut that would explain this? Can't imagine why it recorded fine one clip and was mute on the next. Appreciate any advice. Class is ready to throw in the towel and give up on podcasting. I don't want to see that happen if it is an easy fix. Thanks.