Making a screenshot is a great quick way of showing what is on your computer screen.
Here are the steps for doing it on a windows based computer:
Arrange the screen so it shows what is important.
Press the Print Screen button
Create a NEW Bitmap Image
Name the image so it describes your screenshot.
Right click on the icon for the file and choose EDIT, this will open it up in Paint.
Go to EDIT and PASTE
If you want the whole thing with all the menus, you can just save it and you're done.
If you want to crop it, switch out of the selection tool, then back to the selection tool.
Select the area of the picture that you want in your picture and COPY it .
Close the file without saving
Edit the file again in paint (your image won't be there when you open it)
Select Paste again to put the detail image into the file.
Save the file.
Now you can use your screenshot image on a web page or in some other document.