I know we all love lists of Free stuff, but this is genuinely free software for educational use on Windows PCs. Some of it is a little old, but all of it has great functionality. These packages are in alphabetical order:
Audacity - http://audacity.sourceforge.net/
Sound Recoding software
Blue Griffon - http://bluegriffon.org/
html editing package
Cartoon Story Maker -http://www.education.vic.gov.au/languagesonline/games/cartoon/index.htm
Great for making simple cartoon strips for on-screen display
Dia - http://dia-installer.de/
Nice little drawing package
FreeMind - http://prdownloads.sourceforge.net/freemind/FreeMind-Windows-Installer-1.0.1-max.exe?download
Open Source Mind Map maker.
Hot Potatoes - http://hotpot.uvic.ca/
Great for making quizzes of all sorts, interfaces is a little dated but great nonetheless.
Kodu – http://www.kodugamelab.com/
It's 3D programming. Great job MS!
Libre Office - http://www.libreoffice.org/
Certainly as good as Microsoft Office 2007 and better than many older editions!
Microsoft Mathematics - http://www.microsoft.com/en-us/download/details.aspx?id=15702
Free for education, great for more advanced mathematics
MonkeyJam - http://monkeyjam.org/
Helps you to make stopmotion animations on your PCs & drawings.
Free video editing on PCs, great for those simple projects. They don't call them Microsoft Essentials for nothing!
MuseScore – http://musescore.org/
Notation software, but if nothing else enables you to play those classic songs. (Including Frozen)
Paint.net - http://www.getpaint.net/download.html
The free alternative to Photoshop, great for children with a simpler interface.
The classic app, still useful today!
Scratch Offline Editor - http://scratch.mit.edu/scratch2download/
The bedrock of the new Computing Curriculum.
Sketchup - http://www.sketchup.com/download
Make the world in 3D. Fantastic package.
Small Basic - http://smallbasic.com/
Start making games!