A family of Microsoft word processing software products for creating web, email, and print documents.
It shouldn't make a difference on which computer you are trying to update fields.
If F9 shows/hides field codes, then something has happened to the keyboard assignments. In the Customize Keyboard dialog box, you can look at the current assignments and reassign as necessary.
I'm not sure I understand what happens to the equations when you update fields, or why they are even affected.