I found a thread describing almost exactly the same thing, but it looks horribly technical to me (I am an old man brought up in the age of pencils) so I am too scared to proceed with it. See http://tinyurl.com/3b2qsd.

I don't know what I can do now. I just wanted to try and update a DVD, and I find myself embroiled in a nightmare of technicalities involving the inside of my computer. Not what I expected when I first started this thread, I thought I was just going to need advice on using the editing software.