I cannot connect to SQL server
due to the following error :

Had trouble connecting to server

Server Name: ZAFAR-PC
Error Number: 18456
Severity: 14
State: 1
Line Number: 65536

Identified this error as following: Server is in Single-User Mode (2005)
Source: Error 18456, Severity 14: Login Failed States Database Articles

Probable Solution:

Use "SQL Server 2005 Surface Area Configuration" to add yourself as an administrator on the SQL Server Instance.
In Vista, a Windows admin is not a SQL admin by default - they need to be added.

Source: How to: Connect to SQL Server from Windows Vista

One of the steps is to : In SQL Server Management Studio, connect to an instance of SQL Server.

But i cant figure it out ? like how to ?