Here’s the free (it doesn’t cost money) Windows software I use.
Camstudio – Record screen video. Free alternative to TechSmith’s Camtasia.
Screenshot Captor – Capture, edit, and publish screenshots. Free alternative to TechSmith’s SnagIt. Very nice output.
AVG Anti-Virus – Antivirus. Effective.
CloneSpy – Duplicate file finder and remover. Saved me a bunch of time sorting through gigs of data I’ve accumulated over the last decade or so.
Inkscape – Vector-based drawing program.
Paint.Net – Image effects and simple editing.