"Trash" can get into your basic document (Normal) thus affecting other documents based on it -- In my case, default underlining got into my Normal document I was only able to solve after doing a Word Uninstall/Reinstall

I took the time to do this when I realized I was wasting time trying to troubleshoot the problem to NO avail

Sometimes going around the world to get across the street than simply crossing the street is the best option, IF you have to spend a lot more time finding (or trying to find) the freaking quicker way