I have downloaded and installed PostgreSQL and the Enterprise Manager, and have created a new database, created a table with some fields, and have successfully inserted and updated a few records, all using the Enterprise manager.

In my VB project I have installed the correct Npgsql.dll to \bin\Debug, and successfully referenced it.

However, none of the connection strings I have tried have worked - each one failing as {"FATAL: 28P01: password authentication failed for user "Jonathan""}.

I just *know* my Windows 8 User ID is Jonathan, I also tried HP64\Jonathan, also unsuccessfully.

I tried all these:

Code:
        Try
            Dim con As NpgsqlConnection
            con = New NpgsqlConnection("Server=127.0.0.1;Port=5432;Database=MyEStaffRegister1;User Id=HP64\Jonathan;Password=xxx;")
            'con = New NpgsqlConnection("Server=127.0.0.1;Port=5432;Database=MyEStaffRegister1;Integrated Security=true;")
            'con = New NpgsqlConnection("Server=127.0.0.1;Port=5432;Database=MyEStaffRegister1;User Id=HP64\Jonathan;Integrated Security=true;")
            'con = New NpgsqlConnection("User ID=HP64\Jonathan;Password=101255;Host=localhost;Port=5432;Database=MyEStaffREgister1;Pooling=true;Min Pool Size=0;Max Pool Size=100;Connection Lifetime=0;")
            'con = New NpgsqlConnection("Server=127.0.0.1;Port=5432;Database=MyEStaffRegister1;User Id=HP64\Jonathan;Integrated Security=true;")
            con.Open()
            MsgBox("Connected to Database")
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
The error message is

Npgsql.NpgsqlException was unhandled
BaseMessage=password authentication failed for user "HP64\Jonathan"
Code=28P01
Detail=""
File=src\backend\libpq\auth.c
Hint=""
Line=302
Message=FATAL: 28P01: password authentication failed for user "HP64\Jonathan"
Position=""
Routine=auth_failed
Severity=FATAL
Source=Npgsql
Where=""
StackTrace:
at Npgsql.NpgsqlConnector.CheckErrors()
at Npgsql.NpgsqlConnector.Open()
at Npgsql.NpgsqlConnectorPool.GetPooledConnector(NpgsqlConnection Connection)
at Npgsql.NpgsqlConnectorPool.RequestPooledConnectorInternal(NpgsqlConnection Connection)
at Npgsql.NpgsqlConnectorPool.RequestPooledConnector(NpgsqlConnection Connection)
at Npgsql.NpgsqlConnectorPool.RequestConnector(NpgsqlConnection Connection)
at Npgsql.NpgsqlConnection.Open()
at PostgresTest.Form1.Button1_Click(Object sender, EventArgs e) in C:\My Documents\PostgreSQL\Sample VBNet\Form1.vb:line 71
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoCompo nentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at PostgresTest.Form1.Main() in C:\My Documents\PostgreSQL\Sample VBNet\Form1.vb:line 0
at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
If you can see what I have done wrong, please let me know.

Thank you.