What does the Print Screen Key do?
In old DOS programs, the Print Screen key used to do just that… Print a copy of whatever was on the screen at that time. However, it didn’t work with graphics, so if there were any graphics on the screen at the time, you would get a garbled mess from your printer.
When Windows came along and brought pictures and icons along with it, this created a problem. Now, the Print Screen key copies a picture of whatever is on your screen to the clipboard. Then you can use Microsoft Paint, or another graphics editor to paste it and print it, or put it on your web page.
If you press Alt+PrtSc, it will take a snapshot of the current window only. Paste the picture in a graphics editor or into another application such as Microsoft Word to use the image.