Virtualdub is an open-source video capture and editing tool for Windows. It deals mainly with AVI files, but it can also open MPEG files, and import and export image sequences. It allows you to easily do tasks such as removing sections of a video, applying filters, and exporting audio.
Although Virtualdub has very powerful editing tools and filters, Virtualdub is not an NLE and it does not let you use layers or easily join clips together.
http://www.virtualdub.org/ - Official Site