My Ui Is Not Responding When I Am Using Task Class In C#

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C#

C#4.0

Here is my code :

private void ShowLoadingWindow()
        {
            frmLoading obj = new frmLoading ();
            obj.Show();
        }
       

        private void button1_Click(object sender, EventArgs e)
        {
            Task t1 = new Task(new Action(ShowLoadingWindow));
            t1.Start();
        }

what i am doing is, i am starting a task when the button is clicked and showing a window form as loading.
The form is shown but the problem is the Loading Form UI is not responding.
Please give me the solution. I dont want to use async keywords as i am using 4.0 framework