Very useful utilities

ImgBurn - Handy for burning files / folders / and ISO images to cd / dvd / blu-ray

FunDuc DupFileFinder - Duplicate file finder for Windows by FunDuc software. Exceptionally fast with two comparison methods, and highly accurate. Compares contents along with filename

Daemon Tools Lite - Creates virtual drive to run disc image files without the need of burning them to disc (saves discs).

WolframAlpha - Find what program file extensions open with, and information about file extensions.