Cannot Connect Locally To SQL Server Express

Hi,

I'm trying to connect to a SQL Server 2005 express on my local Windows
XP Professional machine. I've searched the the MS fora and Google
but all the answers I find relate to trying to connect to a remote DB,
not local.



I run the aspnet_regsql.exe program in the interactive wizard mode, and
in the Select the Server and Database step when I click on the Database
drop-down list an error box pops up:



Connection failed

Failed to query a list of database names from the SQL server.

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)



Exactly the same error message appears when I:

* Change the 'Server' name from my computer's name to localhost, 127.0.0.1, or SQLEXPRESS. in the aspnet_regsql wizard.

* Stop my firewall (ZoneAlarm, native Windows firewall is disabled, and I switched off my cable modem at the time).

* Use the SQL Server surface area utility to enable remote connections
with both named pipes and TCP/IP), and also to enable CLR integration
in the Features section.

* Stop the SQL Server service. I did this to see if a different
error occurred, but it's as if aspnet_regsql.exe can't even see the SQL
Server.

* Have an additional instance of SQL Server running under my own username (see below).





I have an ASP.NET project (created by someone else on another computer) which attempts
to open a SQL Server database. It runs fine until the call to
System.Data.SqlClient.SqlConnection::Open() which raises an exception
with exactly the same error string as above (including what's in
parentheses). The connection string is "Data
Source=localhost;Initial Catalog=blah;Integrated Security=SSPI;" where
blah is specific to the company I'm doing this for.



I've created a test ASP.NET project to which I added a SQL
Database. My only option was to create a .mdf file in the
APP_DATA folder. The connection string is "Data
Source=.SQLEXPRESS;AttachDbFilename=|DataDirectory|Database.mdf;Integrated
Security=True;User Instance=True" and it works fine and displays the
data I've put into the database, but in the Task Manager another
instance of sqlservr.exe appears (running under my username; the
existing sqlservr.exe runs under the NETWORK SERVICE username).
Should this happen??



If I stop the SQL Server service (or both of them), an error message in my web browser
appears (no exception is raised because there's no code in the project,
just a data-bound control). The error is the same as above,
except the parenthetical part is "(provider: SQL Network Interfaces,
error: 26 - Error Locating Server/Instance Specified)".



Edit: oh yeah, I've also tried to set up an ODBC data source connected
to SQL Server throught the Control Panel/Admin, but the ODBC applet
can't seem to see SQL Server either.  I only get three options for
data sources: dBASE files (.dbf), Excel files (.xls), and MS Access
Database (.mdb).  If I click on 'Add' and select "SQL Server" and
go on from there, it comes back and says the server doesn't exist or
refuses access.  If I stop the service, the ODBC applet says the
sql server wasn't found.



Can anyone help please?

I'm stumped..