threading / opening a window

Hi guys, so im hoping you can help me with this...

The method "window" below is attempting to launch a new thread, which will open up the window "MyDialog"

the window contains a text box, and a button, so i make the method wait while the mydialog window thread is open...

the user then enters a pin into the textbox, presses the button.... 

the button then adds the "email" string, and the "responcetext" to a dictonary, before closing the window, which should then close the thread, and the code continue.... great! 

this seems to work perfectly when i have one thread open, running this....

        private void window(string input)
        {
                Thread thread = new Thread(() =>
                {
                    MyDialog w = new MyDialog(input);
                    w.Show();

                    w.Closed += (sender2, e2) =>
                    w.Dispatcher.InvokeShutdown();
                    System.Windows.Threading.Dispatcher.Run();
                });
                thread.SetApartmentState(ApartmentState.STA);
                thread.Start();
                while (thread.IsAlive == true)
                {

                    Thread.Sleep(1000);
                }
        }

    partial class MyDialog : Window
    {
        string email;
        public static MyDialog screenMain = null;
        public MyDialog(string emailinput)
        {
            email = emailinput;
            InitializeComponent();
            screenMain = this;
            name.Content = "Please enter the pin relating to " + email;
        }

        public string ResponseText
        {
            get { return ResponseTextBox.Text; }
            set { ResponseTextBox.Text = value; }

        }

        private void OKButton_Click(object sender, System.Windows.RoutedEventArgs e)
        {
            LoginRequest.setMyVariable2(email.ToString(), ResponseText.ToString());
            Close();
        }
    }
}

as soon as i have two threads open, both running this same code at once from seperate threads i get this error happening: 

An unhandled exception of type 'System.InvalidOperationException' occurred in PresentationFramework.dll

Additional information: The Application object is being shut down.

It happens on the Initializecomponent(); line....

and if i continue i get object null errors on the name.Content line

i though if i opened the mydialog window as a new thread again, i would avoid these errors? Im new to coding so appologies if im being stupid here.... 

if anyone can help me out id be very very very grateful!