问题:

I logged into SQL Server 2008 via SQL Server Management Studio using Windows admin account. When I run the command (ALTER LOGIN sa ENABLE) I get the following error.

Cannot alter the login 'sa', because it does not exist or you do not have permission.

回答1:

You account doesn't have permissions. It isn't sysadmin.

CREATE DATABASE requires

Requires CREATE DATABASE, CREATE ANY DATABASE, or ALTER ANY DATABASE permission.

This is (legacy SQL Server 2000 lingo):

sysadmin
dbcreator

If the account is "end user" consider wrapping the call in a stored procedure to hide the permissiosn escalation

Edit, after question update

sa is always sa; you can't disable it as such

You need to grant some permissions to the Windows account using GRANT

回答2:

Follow the advices in this article: http://blogs.msdn.com/b/dparys/archive/2009/09/17/create-database-permission-denied-in-database-master-my-fix.aspx

EDIT: The whole question changed!