A family of Microsoft word processing software products for creating web, email, and print documents.
>> I added 2 page breaks to my document so that I can orient a single page in landscape mode.
You probably meant Section Breaks (Next Page), as a page break would only work with a rotated screenshot of the page (you can't change page orientation for separate pages in the same section).
Have you tried changing the font? Corrupt fonts have been know to cause visual anomalies. Select the whole document and test various fonts. Calibri and Cambria are a must, since they are the newest.
Otherwise, it could be a corrupt parameter in Normal or Preferences. In this case: quit Word; hold Shift; open Word; release Shift after Word stops loading; test.