Thanks Mohammed.

Your link has solved my problem.

I noticed there that I missed using -S myServerName in my DOS command.

I tried the following DOS command, it went well and...

I have turned off the Windows Firewall and tried again. I still get the following error message.

C:\>sqlcmd -U sa

Password: HResult 0x2, Level 16, State 1

Named Pipes Provider: Could not...