Q. How can I paste a copy of the whole computer screen into my document?

This is the "poor man's version."

1. Press Control+PrtScn buttons to copy. I want to press Shift+Ctrl+F4 on a Mac (you have to size the shot you want).
2. Open Word. You may want to stretch the margins or change the orientation to landscape from the default portrait to get a better fit.
3. Press Control (or Mac Command)+V buttons to paste.

If you need to edit it, you can type PBRUSH )Paintbrush on Windows) in the search box on the Start button. I didn't edit pictures much on a Mac so I don't know what to recommend there. Just paste and crop/resize the image you need and re-paste into Word.