Remote connection problem with multiple version number SQL Server

Install the system Win7 has been unable to install sqlserver2012, later installed sqlserver2005, the former period of time because of the need to use sqlserver2012, try to install again, incredibly installed successfully. However, the sqlserver2012 remote connection is always unsuccessful, and the host name \ Instance name succeeds. Find a lot of methods on the Internet, have not succeeded. I'll list all these methods first.

1, double-click on the right side of TCP/IP

Open the IP Address option, pull to the top of the Ipall, set a tcpport, such as 1433 or 1444, set the OK, and restart the corresponding instance of SQL Server service (TCP/IP protocol is not enabled, to enable), for example.

2, when connecting, pay attention to the format, format: "IP address \sqlserver instance name (this is usually seen in the service), port (this port is the TCPPort set in the previous step)", for example

This normal situation is not a problem, of course, if the SA account to be enabled, this is not said, and my computer so connected, always prompt

Unable to connect to 127.0.0.1\sql2012.
A network-related or instance-specific error occurred while establishing a connection to SQL Server. Server was not found or could not be interviewed. Verify that the instance name is correct and that SQL Server is configured to agree to a remote connection. (Provider:sql Network Interfaces, error:26-Error locating the specified server/instance) (Microsoft SQL Server, Error:-1)

Sometimes prompts for memory access or writes

Then I did the following 2 actions

1. Open cmd, enter netsh winsock reset, reset the Winsock folder, and restart the computer

2. Change the "built-in account" from "Network Service" to "Local system" and restart the service of the corresponding instance of SQL Server

This is OK, or for example the connection mode

Connection Successful!

Remote connection problem with multiple version number SQL Server