Sql-server – MS SQL Server 2008 R2 Product Key

If SQL Server is started in single-user mode, any user who has membership in the BUILTIN\Administrators group can connect to SQL Server as a SQL Server administrator. The user can connect regardless of whether the BUILTIN\Administrators group has been granted a server login that is provisioned in the SYSADMIN fixed server role. This behavior is by design. This behavior is intended to be used for data recovery scenarios.

So if you have access as an administrator to the machine, you can still access SQL Server - but single-user mode will be required.

Hope this helps.

Raj

You can use intall the same license on a single machine as many times as you want (instances) if you are licensing by CPU. With server+ User or Device CALs you license it for the operating environment and can also install it as much as you want on the same machine.

http://www.microsoft.com/sqlserver/2008/en/us/licensing-faq.aspx