Changed root password and no su works...

[Tim Watson]

OK. I'm new to sudo here and have searched everything I can and found no
answer to this...

I was playing around with sudo and think I had it working the way I wanted
it to....

then I went and changed the root password.....  now everyone can just su to
root...
What did I do... and what do I need to do to get it back to how it was....

Many thanks....

Tim W