我用sa账号登陆sql server 失败，什么原因呢？下面是错误信息：An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)
你不是在局网内？
Click Start, point to Programs, point to Microsoft SQL Server 2005, point to Configuration Tools, and then click SQL Server Surface Area Configuration.
On the SQL Server 2005 Surface Area Configuration page, click Surface Area Configuration for Services and Connections.
On the Surface Area Configuration for Services and Connections page, expand Database Engine, click Remote Connections, click Local and remote connections, click the appropriate protocol to enable for your environment, and then click Apply. Note Click OK when you receive the following message:
Changes to Connection Settings will not take effect until you restart the Database Engine service.
On the Surface Area Configuration for Services and Connections page, expand Database Engine, click Service, click Stop, wait until the MSSQLSERVER service stops, and then click Start to restart the MSSQLSERVER service.我按照这个步骤做，MSSQLSERVER ->Database Engine->Service:
状态：stop.
当我start时，报如下错误：
A error occurred while performing this operation.
为什么不能start呢