Microsoft Data Access Components (MDAC) versions earlier than 2.6 can't connect directly to a SQL Server 2000 named instance by using the \\sqlserver\instance_name format. Of course, you can gain this functionality by upgrading to MDAC 2.6. But if you're not ready to upgrade, you can still connect to a SQL Server 2000 named instance by using a client-side alias for the SQL Server instance. Simply start the Client Network Utility, and from the Alias tab, click Add and enter the appropriate network connection information. Your MDAC 2.5 application can now use the alias name that points to the named instance.