prevent user with ID 1 edit I would like to prevent admin site (user id 2) to remove or change password user with id 1 although i need to admin add users and edit another users.
how to do this?
This is a Drupal no, no.  Leave root user alone. Just leave it.  If you are worry about security, change the username admin, to something else (admin is the most commonly use name hacker try to use).   Then just use uid 2 to administrate the site.