Need help! (ubuntu 11.10)

Somehow managed to do a stupid thing -- that is, from the

   User_name in menu bar-->User Accounts

I managed to make all my login accounts 'standard' (normally at least one
login account is 'admin'). When I a try a 'sudo cmd', it says that the
user "is not in the sudoers file". When I try to go back to the User
Accounts
gui and use the unlock icon and enter the correct password, the error
is "An application is attempting to preform an action that requires
privileges.
Authentication as super user is required to perform this action".

Some linux web pages have recourse assuming the super user account password
has been lost and you may fix it by booting up the session with 'single'
user mode and changing the password via a root command 'passwd'. Since I
can still login into the account which should have super user privileges,
it is not clear that single user mode to change the password will correct
my lack of admin privileges problem.

BTW, I have not found single user mode recipe for ubuntu 11.10 on the web
that works so I don't know if re-setting the password will fix my lack of
admin privileges.

Two issues:
 1) How do I remedy my issue in restoring my "admin" privileges
 2) The gui should always make sure that at least one login account has
    'admin' privileges.

If fixing issue 1) involves the 'single' user mode, where is a good web
recipe for ubuntu 11.10.

David


-- 
David Lopez
Software Engineer