Dave Mason shares a few useful tools::
I’m a proponent of “Show me, don’t tell me”. Screen captures go a long way toward that. Sure, Windows has Paint, but Paint.NET is a bit more advanced. I almost always have an instance of it open in the background. Hit the Print Screen keyboard button and paste (CTRL + V) it into Paint.NET (you can also use the ALT + Print Screen key combination to screen capture just the active window). From there you can do anything: trim down to just a specific part of the image, add some red arrows or circles for emphasis, blur/obscur any sensitive data that’s in the image, etc. I take tweaked screen shots and paste them into just about anything…Word documents, email, even Twitter.
As far as it goes, I think I use different tools than Dave across the board, save for 7Zip. I like Notepad++, SnagIt, WinDirStat, LastPass, 7-Zip (yay for agreement), and mRemoteNG, and despites headphones respectively. But that goes to show that there are plenty of good alternatives for products and it’s worth trying a few out.