Whilst doing a Camtasia 7 screen capture using Powerpoint, Irfanview and Firefox 24 on Windows 7 64bit PC , I noticed that the audio is recorded but not the video. When Firefox is closed the Powerpoint and Irfanview elements are recorded correctly. The screen capture was repeated using Firefox and then Internet Explorer as the browser, the black screen returned on both occasions. Swapping Internet Explorer for Chrome and then Opera, the screen capture was recorded correctly thus there is an issue with Firefox and Camtasia where only the audio is being recorded.