Add to your .emacs,
(auto-fill-mode -1)
If there are hooks for specific modes, you will need to zap those as well. My suspicion is that you do not actually have auto-fill-mode on by default in all modes, but with the information you have supplied, at least this should be a starting point.
A reasonable safeguard would be to also disable auto-fill mode from `text-mode-hook’:
(remove-hook 'text-mode-hook #'turn-on-auto-fill)
You may need something similar for other modes as well.