Hi Steve,
The field code display setting, which you can toggle on/off via Alt-F9, is a system setting sored in the Windows Registry, not a document setting, so it only affects documents on the PC concerned. And, as it's a registry setting, repairing, uninstalling/reinstalling Word and editing/deleting the Normal template won't affect it.
A couple of questions:
1. Are you saying that pressing Alt-F9 doesn't work?
2. How did you remove the zotero addin? See:
http://forums.zotero.org/discussion/...e-word-plugin/ for uninstallation advice.