sqlcmd not working after installing sql server 2005 express

I downloaded the 53.5 MB setup of SQL Server 2005 Express from this URL:

Microsoft SQL Server 2005 Express Edition

Then I ran sqlcmd by going into command promp , but it shows error

HResult 0x2, Level 16, State 1
Named Pipes Provider: Could not open a connection to SQL Server 2.
Sqlcmd: Error: Microsoft SQL Native Client : 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..

Sqlcmd: Error: Microsoft SQL Native Client : Login timeout expired.

Then I downloaded and installed Sql Command Line Utility from this URL:

Feature Pack for Microsoft SQL Server 2005 – November 2005

Then also it shows the same error.

Then I installed Sql Native Client, then also it didn’t work. But when I installed Management Studio, then from Management Studio the connection is established, but not from sqlcmd from Command Prompt.

Please help.