unwanted horizontal margin line in Word

[jonplaywright]

I have Word 97-2002 on my desktop and Word 2013 on my laptop. Just upgraded both to Windows 10, which may be related to the issue, or not.



On the odd-numbered pages of one of my documents, I've got a faint horizontal line showing up in the margin on pages that are numbered. It's maybe 3/4" from the top of the body text. It doesn't show up on even pages, and it doesn't show up on pages that don't have page numbers/headers.

It seems just to be in this one document, and a friend with both a PC and a Mac is seeing it too. But neither of us can figure out quite what it is and how to get rid of it. Help!

Thanks.

Jon