When having an issue with screencast not working (either taking over the entire screen or not counting down), this could be related to the microphone not working.

The following steps should be a workaround to ensure that the camera works:  

1. Go to Control Panel, click on  Sound 
   
   
    
2. Click on the Recording tab. 
3. Select the microphone.  
4. ​​​Click on the Properties button.  
   
   
    
5. Click on the ​Advanced tab. 
6. Uncheck the box "Enable audio enhancements". (You may need to close TPS first or restart).​​​