Hello,
I have realised a bug in Bandicam. When you have skype open and you launch / try to record with bandicam, Skype crashes straight away but when you click "Close this program" after it has gone none responsive, the sound comes back. I can record a video if you want me to show you?
Edit: To use Skype again normally you need to CTRL + ALT + DELETE then end the process. (Skype.exe)