SQL 2005 and .NET 1.1 (And things had been going so well...)

I installed all the new bits, and things were working fine. I come back from lunch, and it's like my compy has lost its mind (or maybe I have). 
 

System.Data.SqlClient.SqlConnection sc = new System.Data.SqlClient.SqlConnection();
        sc.ConnectionString = "data source=(local);integrated security=SSPI;persist security info=False;Pooling=false;";
        sc.Open();

If I put this code in a plain old 1.1 app, I get "SQL Server does not exist or access denied." If I put it in an empty 2.0 app, it works. Thoughts?

Try changing "datasource=(local)" to "datasource=localhost"

Nope. Sorry, that didn't help.

Also, I checked in Configuration Manager, and all of my connection protocols are enabled. I don't see the connection attempt, failed or otherwise, when I attach to the server with the Profiler.

Appropriate that this happened on Halloween, I suppose...

Check the security on the sql login accounts for asp.net 1.1 and 2.0, they may be different accounts.

That did it. Thanks, Blowdart!

You should also be able to specify Network Library=dbmslpcn. See the documentation for the SqlConnection.ConnectionString property. The default value for this parameter in 1.1, which specifies the client network library, is 'dbmssocn' which is the TCP/IP library. The documentation does say that 'If you do not specify a network and you use a local server (for example, "." or "(local)"), shared memory is used.' Perhaps a bug stops this working on 1.1, or the documentation is in error.
 
You might prefer to switch network libraries and reduce your security exposure by disabling TCP/IP.