Pressing PrintScreen will capture the entire screen to the Clipboard, whence
it can be pasted into a document. Alt+PrintScreen captures the active window
(a dialog, for example). These are crude tools. If you want to have finer
control, get a dedicated screen capture program such as SnagIt from
TechSmith (
www.techsmith.com), which allows you to capture specific menus
(including scrolling ones) and other elements, apply edge effects, and save
in a wide variety of graphics formats. If you settle for PrintScreen, your
best bet is to paste your screen shot into a graphics app (even MS Paint)
and crop the picture, save, then insert into Word. While you can crop the
graphic in Word, you don't actually reduce its size that way because the
cropped portion aren't removed, just hidden (and you may find that they'll
print anyway on some printers).