1. TCP/IP

run the Computer Management applet from 
    Control Panel→Administrative Tools→Computer Management, 
    where you should find the configuration manager installed 
        (Services and applications)
            SQL Server Configuration Manager

then:
->Expand SQL Server Network Configuration-> Protocols for MSSQLServer 
	-> Right click on TCP/IP -> Enable
	-> Double Click on TCP/IP 
	-> IP Adresses -> put port 1433 under IPAll TCP port.

(see tcp_ip.png image)

2. creating user - if user 'sa' exists, create user 'sas'

USE [master]
GO

CREATE LOGIN "sas"  
    WITH PASSWORD    = N'SQL',
    CHECK_POLICY     = OFF,
    CHECK_EXPIRATION = OFF;
GO	
EXEC sp_addsrvrolemember 
    @loginame = N'sas', 
    @rolename = N'sysadmin';

- in order to login with the user, we have to enable SQLServer auth:
	- open Connection on the database -> Properties -> Security -> SQL Server and Windows Authentication mode radio button
	(see image sql_server_auth.png)
	
- possible problems -> if user cannot be created -> run MSSQL Manager as admin	

restart SQLServer
