Using Word 2002 from Office XP Pro. All updates etc in place.

I needed to install Japanese support in Office in order to include some
Japanese text in a document I'm working on. Now I have these funny L-shaped
marks in each of the four corners of all my documents. They seem to be
defining where the margins (top, bottom, left, right) are. The mark in the
upper left hand corner looks sort of like this:

_|

The other marks are turned around this way and that so that the open side of
the angle faces the corner it's in.

Why did this happen? Can it be undone?