Thinking about shooting an instructional viceo where I'll use the screen-capture software I got when I just recently purchased PowerDirector 17 Ulltimate. But there are proabably going to be some on-screen things I'd like to sort of "Blur out" to hide, for security reasons, so that end-users who see my video can't see it, before I produce it. How do I do that, after I capture some video?