|Simply hit the "print screen" key when you have whatever you wish to do the screenshot of in the foreground (you can hold the "alt" key while doing so and the screenshot will only be of whatever window is in the foreground).|
I usually fire up MSPaint and paste it in there and save it as a .bmp or else I paste it in irfanview and save it there as a .jpg.
.jpg files are smaller so if you're sending it via email attachment, .jpg is the best format to use.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.