Open network library cofiguration

Click Start, click Run, type cliconfg, and then click OK.

You may not be able to connect to an instance of SQL Server that is configured to use the Named Pipes server network library on a computer that is running Windows XP Service Pack 2

[Named Pipes]SQL Server does not exist or access denied.
[Named Pipes]ConnectionOpen (Connect()).

or

Unable to connect to server <SQL Server instance name>

Server: Msg 17, Level 16, State 1
[Microsoft][ODBC SQL Server Driver][Named Pipes]SQL Server does not exist or access denied.

or

Cannot connect to <SQL Server instance name>

Solution

Enable TCP port 445 by changing the network connection settings.

To do this, follow these steps:

1. Click Start, and then click Run.
2. In the Run dialog box, type Firewall.cpl, and then click OK.
3. In the Windows Firewall dialog box, click the Advanced tab.
4. Under Network Connection Settings, click your network connection, and then click Settings.
5. In the Advanced Settings dialog box, click Add on the Services tab.
6. In the Service Settings dialog box, set the values as specified below, and then click OK.

To work around this problem, you can use the TCP/IP sockets network library. You can create an alias for the computer that is running SQL Server that uses the TCP/IP Sockets library or you can use TCP/IP as the only default enabled protocol. To add a SQL Server alias that uses TCP/IP Sockets library, follow these steps:

1. Click Start, click Run, type cliconfg, and then click OK.
2. In the SQL Server Client Network Utility dialog box, click the Alias tab, and then click Add.
3. In the Add Network Library Configuration dialog box, under Network libraries, click TCP/IP.
4. In the Server alias box, type the IP address of the computer or the name of the computer that is running SQL Server, and then click OK.