You can disable root (System->Access->Users select root and check Disabled).
If you're using shell access, you should (if not done already) enable sudo usage (System->Settings->Administration), otherwise (at least the last time I checked), you can not elevate your privileges in the shell.
If you're using shell access, you should (if not done already) enable sudo usage (System->Settings->Administration), otherwise (at least the last time I checked), you can not elevate your privileges in the shell.