In the early days of personal computers, the Print Screen button on your keyboard (above the arrow keys and to the left of the number pad for those of you who have never bothered looking at the keys you don’t use) would actually print what was on your screen. But everyone who has tried it knows that in Windows, it doesn’t print anything. So what does it do? It takes a “snapshot” of whatever is on your screen. Then you can paste that snapshot into a document. So if you are developing procedures or documenting an error, you can paste a picture of your screen into your document or email instead of just describing what it looks like. Pasting a screen shot is just like pasting anything else. In most programs that means choosing Paste from the Edit menu, right-click & Paste or Ctrl+V would all work.
There are two basic options for using this feature. (1) As I said before, pressing Print Screen will capture an image of your whole screen. Or (2) you can use Alt+Print Screen to capture just the current window. In many situations that is more helpful than capturing your entire screen.
What if you want an image of less than a whole window? Then you have to either crop the image down to just the part you want using some other software, or buy a specialized screen capture program, which can give you many options. Some are even available for free.
One other related feature in Windows allows you to capture just the text from an error screen. Make sure the error message is the active window, then press Ctrl+C (the standard copy shortcut in Windows). When you paste that, instead of getting a picture of the error message, you will get the actual text, without any of the graphics.