非常郁闷的一天，客户突然打电话说网站不能运行了，打开页面报以下错误
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
检查了一下数据库配置，没问题，已前运行都是好的，不知服务器被人改了什么东西。
数据库配置如下：
连1433端口没问题，用其他机器也可以连上
连接字符串绝对没问题 用的Nhibernate
<add key="ConnectionString" value="Server=Ip地址\SQL2005;initial catalog=ServerOldDB;User id =sa;Password=111" />
sessionState 记录在数据库里的
<sessionState mode="SQLServer" stateConnectionString="tcpip=127.0.0.1:42424" sqlConnectionString="data source=Ip地址\SQL2005;user id=sa;password=111" cookieless="false" timeout="20" />
以前运用正常，不知客户在服务器上做了什么，他们说没改动，现在就不行了，一直找不到原因
服务器上还有一个 SQ2008的版本和Oracel，以前就有，运行没问题，太诡异了。
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SqlServer browser都没启动，怎么远程连接？