formatting problem

Hi, I am new to this forum stuff so i don't know the ropes. I am just having a Word 2000 (yep, its old) formatting problem that is making me crazy and i thought i would try.

 

Here's the problem: I am working on a manuscript that is over 200 pages long and starting on about page 197, I am plagued by mysterious bold, dashes, like page breaks only bolder, that separate different part of the text. When I go to the end of the preceding paragraph and hit delete, the line will go away, only to reappear when I hit enter. If I don't hit enter and allow the following sentence to be a part of the paragraph before the offending "break", the break reappears a few lines farther down. It only started at this late stage of my manuscript. Thanks for any advise you can give me.