http://blogs.msdn.com/sqlserverfaq/archive/2009/03/20/how-to-list-all-the-installed-sql-server-on-the-server-using-tsql.aspxThe SQL Server instances are independent and do not know each other. The method is to query the registry to find the instances. You can use the following Script to list all the installed sql server on the server using TSQL Solution ========= Set NoCounten-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/sqlserverfaq/archive/2009/03/20/how-to-list-all-the-installed-sql-server-on-the-server-using-tsql.aspx#9493624Sat, 21 Mar 2009 00:32:51 GMT91d46819-8472-40ad-a661-2c78acb4018c:9493624infoblog &raquo; How to list all the installed SQL Server on the Server using TSQL<p>PingBack from <a rel="nofollow" target="_new" href="http://blog.a-foton.ru/index.php/2009/03/20/how-to-list-all-the-installed-sql-server-on-the-server-using-tsql/">http://blog.a-foton.ru/index.php/2009/03/20/how-to-list-all-the-installed-sql-server-on-the-server-using-tsql/</a></p>