A family of Microsoft word processing software products for creating web, email, and print documents.
Select a passage & change the font to something contemporary, such as Cambria... Does that have any impact?
My guess is that files as old as what you claim most likely were created using either fixed-width or Postscript fonts, neither of which display well in the more current software.
Without the nonprinting characters being displayed I can't even hazard a guess regarding the "random returns", though :-)