Authenticate User

[primagic]

I am having troubles authenticating users against an sql server database.

I have a table with UserID, Username (email address), Password (hashed) and a GUID field.

I have the following code which authenticates a user. This used to work before I hashed the passwords.

Function DBAuthenticate(ByVal strUsername As String, ByVal strPassword As String) As Integer
        Dim conUsers As SqlConnection
        Dim strConnection As String
        Dim cmdSelect As SqlCommand
        Dim parmReturnValue As SqlParameter
        Dim intResult As Integer

        strConnection = ConfigurationManager.ConnectionStrings("HostLinkConnectionString").ConnectionString
        conUsers = New SqlConnection(strConnection)
        cmdSelect = New SqlCommand("AuthenticateUser", conUsers)
        cmdSelect.CommandType = CommandType.StoredProcedure
        parmReturnValue = cmdSelect.Parameters.Add("RETURN_VALUE", SqlDbType.Int)
        parmReturnValue.Direction = ParameterDirection.ReturnValue
        cmdSelect.Parameters.AddWithValue("@Username", strUsername)
        cmdSelect.Parameters.AddWithValue("@Password", strPassword)
        conUsers.Open()
        cmdSelect.ExecuteNonQuery()
        intResult = cmdSelect.Parameters("RETURN_VALUE").Value
        conUsers.Close()
        If intResult < 0 Then
            If intResult = -1 Then
                lblMessage.Text = "Login failed"
            Else
                lblMessage.Text = "Login failed"
            End If
        End If
        Return intResult
    End Function

Login button code:

Protected Sub btnLogin_Click(sender As Object, e As System.EventArgs) Handles btnLogin.Click
        If IsValid Then

            If DBAuthenticate(txtUsername.Text, txtPassword.Text) > 0 Then
                FormsAuthentication.RedirectFromLoginPage(txtUsername.Text, False)
                Session("Username") = txtUsername.Text
                Response.Redirect("dashboard.aspx")
            End If
        End If
    End Sub

My problem is that it always comes back Login failed!