I have a user experiencing a problem with Excel 2007. She's running a Windows XP machine. When she types, text isn't displayed in the field she's typing in. It is displayed in the toolbar at the top. When she tabs to the next field, the text becomes visible. So, it's not white text on a white fill. Any ideas?

Look in your Tools > Options > Edit> [x] Editing directly in cell and make sure that's checked.