"A network-related or instance-specific error occurred while establishing a connection to SQL Server" is finally resolved.

To other people do the site is not connected to the database. Baidu has a lot of, finally know their fault in where.

Reported

"A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or is not accessible.

Verify The instance name is correct and that SQL Server is configured to allow remote connections. (provider:named Pipes provider, error:40-could not open a connection to SQL Server) "Error

1, first think of starting the database, log on the user, the database login failed "No, steal a picture of others"

2, the second step, start the SQL Server Configuration tool

The interface is well-debugged:

When you first start debugging, SQL SERVER (MSSQLSERVER) is stopped and runs as follows at startup:

3. The next step must be to open < event log >.

Window Event View "If you do not know where to refer to the following document"-------------------------------------very useful
http://product.pconline.com.cn/itbk/software/win8/1211/3060037.html

The wrong hint is useless, and then you see " application " in the window log, showing

Unable to start application domain windowsservice_0. Error: Microsoft.ReportingServices.Diagnostics.Utilities.EvaluationCopyExpiredException: this Microsoft SQL Server The evaluation period for Reporting Services instances has been over. Licenses are now required.
4, this step to understand what is wrong, next is the SQL Server version upgrade First Step : Open version upgrade

Step Two: Enter the Product key, type the key

Step three: always point to the next step until the upgrade is complete.
SQL Server Developer (development): Pttfm-x467g-p7rh2-3q6cg-4dmyb
SQL Server Enterprise Edition: JD8Y6-HQG69-P9H84-XDTPG-34MBB

Note:
If you select the "version Upgrade" General Prompt "failed" and require "restart the computer", please close the server in the process and other services.
If the above operation is not connected to the server, modify the system time (put the time ahead) or go down to see ↓↓↓↓↓↓
If the issue is still not resolved or if the evaluation period is over (it is said to be a bug that SQL2008SP1 is not installed))
1. Start-to-run- Regedit
2. After opening the registry, locate and put the CommonFiles in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL server\100\configurationstate Change the value to 3
3. SQL Server Installation Center, maintenance, version upgrade once again (because the database has been upgraded earlier, so this time only with the upgrade Share feature components------drop-down select to see)
4. After the above operation, your SQL Server 2008 is working again.

This is very important, not.

--------------------------------------------below for reference only--------------------------------------------

which

run services.msc to change the startup type of the properties of WMI Rerformance adapter to Automatic, but it does not seem to affect.

Attach a registry to the

"A network-related or instance-specific error occurred while establishing a connection to SQL Server" is finally resolved.