Cannot Connect to SQLEXPRESS Instance

I have intstalled SQL Server Express 2008R2 on a Windows 7 computer which is in a P2P network. The router has set port forwarding to allow access through the firewall so I can address it with an address on NoIP. That seems to be working fine, at least for port 80 and I assume also for port 1433. I have opened port 1433 for both inbound and outpound traffic; set SQLEXPRESS to accept both Windows Authentication and SQL login; started the SQLServer Browser and done everything else I can find on E-E and MSDN. I still cannot connect to the instance.
This first appeared when I tried to use the Upsizing Wizard in MS Access 2003 to create the SQLServer db on the server computer. It works fine on my development computer but cannot find the instance on the other computer.
Next, I created a small database on the server (TestDB) with only three records and wrote a VB2010 program to connect to the database. No joy. The error was:

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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

The connection string was:

Server=http:\\tlccdb.servehttp.com\SQLEXPRESS;Database=TestDB;User ID=dick;Password=pwd

I get the same result when http:\\tlccdb.servehttp.com is replaced with my internal address of 192.168.0.192.

Suggestions on how to properly set this up would be greatly appreciated. This is for a non-profit that cannot afford hosting so we need to be able to use NoIP or a similar service. The test program is attached.

Imports System.Data.SqlClient
Public Class Form1
    Dim cn As New SqlConnection

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        rtbResult.Clear()
        Try
            Me.Cursor = System.Windows.Forms.Cursors.WaitCursor
            With cn
                .ConnectionString = TextBox1.Text
                .Open()
            End With
            Me.Cursor = System.Windows.Forms.Cursors.Default
            rtbResult.AppendText("Connection Succeeded!")
        Catch ex As Exception

            rtbResult.AppendText("Connection failed: " + vbCrLf + ex.Message)

            Me.Cursor = System.Windows.Forms.Cursors.Default
        End Try
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        If cn.State = ConnectionState.Open Then cn.Close()
        cn = Nothing
        Me.Close()
        End
    End Sub
End Class

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