I have just bought Sony Vegas Pro Edit 17 and im a complete rookie to Video editing so i thought id try. However, the screen capture feature will not work as whenever I click "Capture Screen", the video and audio source menu which pops up is completely blank (See below). I am using Windows 7 Ultimate and have aquired Vegas through steam. Does anyone know if this is a common issue and if there is a way to rectify this?

Many Thanks