if I record my computer screen from "camstuido", how do I edit the video? To take parts out and such.
Just put the videos into Windows Movie Maker. It's the number one worst video editor in existence, but it's free, which is what's important here.
Another way is to choose a screen recorder which allows you to do video editing such as DemoCreator or BB Flashback 2. Both them are shareware but worth of penny.