I am trying to produce video from Camtasia, producing them in Screencast. After finishing producing, the video shows up in the screencast file but will not play (see the most recent one at: http://www.screencast.com/t/WPJ39XtK). When I click on the start button, nothing happens. This did not occur when I produced videos when I bought Camtasia one month ago. I have a Lenovo T440s with Windows 7. This is a big and urgent problem since I need to produce lectures for University teaching.