Windows Movie Maker used to come pre-installed on Windows but no longer does. Microsoft has stopped supporting it and making it available. If you still have access to it, however, it is a solid basic video editing tool.
Free screencasting software that works from your browser. You can make an account, but you don't have to. You can make a video and publish it immediately to the web or download it and edit it further. Free accounts will include a watermark in the corner of the video.
Free, downloadable software that will capture videos or screenshots. You can download images, but the videos go directly online with a link to them. Jing opens automatically when you start your computer and will appear as a yellow "sun" on your desktop. It's excellent for making "quick and dirty" tutorials.