Network-related or instance-specific errors occur when you establish a connection with SQL Server. The server is not found or cannot be accessed. (Provider: named pipeline provider, error: 40-cannot open to SQL s

The following error occurs when connecting to the SQL Server 2000 database:

Network-related or instance-specific errors occur when you establish a connection with SQL Server. The server is not found or cannot be accessed. Verify that the Instance name is correct and SQL server is configured to allow remote connection. (Provider: named pipeline providesProgram, Error: 40-unable to open the connection to SQL Server)

An error is prompted when you connect to the SQL Server 2005 database! The error message is as follows!
An error occurred while establishing a connection with the server. When you connect to SQL Server 2005, the default setting does not allow remote connection to SQL Server may cause this failure. (Provider: named pipeline provider, error: 40-unable to open the connection to SQL Server)
I installed SQL Server2000 first and then SQL server2005. There are many solutions on the Internet!
The following is a list:
1. In the Start menu, there is an SQL server2005 peripheral program configurator under SQL server2005 in the program. Select the peripheral configurator of the service and connection, and select remote control in the database engine, change the local connection and remote connection to use TCP/IP and named pipes at the same time! Save. Close the connection to the database server and click "reconnect!

2. The data source in the database connection string in the configuration file web. config uses the name of the local server. Do not use an IP address, loacl, or.
Example: <add key = "statdb. connectstring" value = "Data Source = MICROSOF-9D13DF; initial catalog = users; user id = sa; Password = sa"/>

3. Delete the default database link string in the IIS configuration, because after SQL server2005 is installed, the default connection is 2005.
My computer, management, default website in IIS configuration, right-click to view properties, select your version for Asp.net version, then, delete the default string link in edit configuration and edit global configuration!

Modify and edit global configurations

If the red circle contains the default database connection string, remove it!

4. Install SQL Server patches.
This prompt is displayed when you view the database logs!
You have known security vulnerabilities when using Microsoft SQL Server 2000 or Microsoft SQL Server 2000 Desktop Engine (also known as MSDE) and Microsoft Windows Server 2003. To reduce computer attacks by some viruses, Microsoft SQL Server 2000, MSDE or both of the TCP/IP and UDP network ports are disabled. To enable these ports, you must install a patch from your http://www.microsoft.com/ SQL /downloads/default.asp or http://www.microsoft.com/china/ SQL /downloads/default.asp, or the latest service package for Microsoft SQL Server 2000 or MSDE.
Patch SP4 for SQL Server 2000

Download the patch and add it!

5. Modify the remote connection port of SQL server
when SQL Server is installed, the latter modifies the remote connection port of SQL Server, the original port is 1433. When I checked it, it was changed to port 1058.
change it to port 1433!
in the Start menu, there is a server network tool under SQL Server2000 in the program. Select TCP/IP and click Properties to edit its port
select TCP/IP to modify its properties
set the default port to 1433