As a technical writer, I often have to take screen captures or "screen shots" to illustrate a software application or system. A convenient and perfectly adequate tool for the job is the freeware program
ScreenHunter from WisdomSoft. It's currently up to version 5. If you're willing to pay, you can have a much more versatile version.
Thanks to STC member Ed Beliczynski of ExtendMedia, Inc., who originally recommended ScreenHunter to me and who is a fount of information on low-cost software tools.