The network path was not found in windows 7

when I'm running http://localhost/ in my local PC getting this error. But what does it mean?

The network path was not found
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.ComponentModel.Win32Exception: The network path was not found

Source Error:

An unhandled exception was generated during the execution of the current web request. Information 
regarding the origin and location of the exception can be identified using the exception stack trace 
below.

Stack Trace:

[Win32Exception (0x80004005): The network path was not found]

[SqlException (0x80131904): 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: Named Pipes 
Provider, error: 40 - Could not open a connection to SQL Server)]
System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, 
SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String 
newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString 
userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, 
Boolean applyTransientFaultHandling, SqlAuthenticationProviderManager sqlAuthProviderManager) +907
System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, 
DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection 
owningConnection, DbConnectionOptions userOptions) +334

Version Information:

Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3062.0.