I'm having a recurring problem with (1) field codes just appearing in a Word
document and (2) not being able to turn them off.

The field codes are mostly attached to headings, although they sometimes are
attached to other text.

I cannot find anything in the help files that tells me how to turn off or
remove these. They show up on the screen only - they don't show up when the
document is printed.

My questions:
1. How did these field codes get into my document?
2. Could they be related to sharing files among users with different
versions of Word (I have 2003, but some of my colleagues are using an earlier
version).
3. Most important: how do I turn the wretched things off?