Lowell (2/27/2012)
adding the login is not enough...did you add them to the server role as well;something like this is what you are after, i think:
--Add/Restore Restore Builtin\Administrators
EXEC sp_grantlogin 'BUILTIN\Administrators'
EXEC sp_addsrvrolemember 'BUILTIN\Administrators','sysadmin'
after you've done that, make sure you are really part of the Builtin\Administrators group:
EXEC master..xp_logininfo
@acctname = 'Builtin\Administrators',
@option = 'members' -- show group members
does your windows login appear as part of that result set?
I have the same issue but even after adding BUILTIN\Administrators, I am not able to log on with any account in the Administrators group (except for the user Administrator that has a separate login configured). I have executed the mentioned xp_logininfo SP and it lists the users in the Administrators group but they don't work as logins for the Database Engine. I can use them to login for other parts of the sql server, though. I did check that 'BUILTIN\Administrators' is a member of the sysadmin role.
I am at a loss right now.