how can I film my screen for a video?

Hi, it's me again.
Since I received really good software recommendations here, I have another question for software 

I would like to make a movie (I'm already used to editing software such as adobe premiere) and now I need a tool to film what I'm doing on my screen. Like I'm entering something into google and clicking on one of the results --> this is supposed to be part of my movie. It kinda hart to explain, do you know what I mean?

Is there a tool where I can click some kind of start and stop buttons and it saves the movie (of what I'm doing in between) as an .avi file? This way, I would be able to import the file into premiere...

it would be great if you guys knew something to help me out 

Some people recommend the "auto screen recorder", which is also available as a free version:
http://www.wisdom-soft.com/products/autoscreenrecorder.htm


I made good results with the also free "Camstudio":
http://www.camstudio.org/