I assume you are using WORD (Version?)
Two things to check. First in page set up that the margins are set to make full use of the page and that the header and footer settings are set to the minimum. This would explain why you have margins set outside the printable page (i.e.they are beyond the limits of your printer). If the footer is set too high you may get the big gap at the bottom of every page.
Secondly check that the paper size is set correctly. Not to "letter" instead of A4 for example.