Question

Why MS Word is so slow editing even for new computers with plenty of RAM 16GBytes i7?

Answer 1

May be, your machine is suffering with malwares or virus. if your computer is not attacked by a virus then might be some files are either corrupted or destroyed.

Solutions:

Run anti-virus.

Run Checkdisk utility

re-install ur Ms Word

or use lower version of Ms word

of 2010 or 2016.