C#

<br />
//in Home form<br />
private void button3_Click(object sender, System.EventArgs e)<br />
		{<br />
			<br />
			EnggHome enggH = new EnggHome();<br />
			enggH.Show();				<br />
			this.Visible = false;				<br />
			<br />
		}

<br />
private void button3_Click(object sender, System.EventArgs e)<br />
		{	<br />
			<br />
			this.Dispose(true);<br />
			this.Close();<br />
<br />
			HomeForm Hom = new HomeForm();<br />
			Hom.Dispose(); 	<br />
		Hom.Close();<br />
			<br />
		}

public class EnggHome : Form
{
     private Form _parentForm;

     public EnggHome(Form parentForm)
     {
          this._parentForm = parentForm;
     }

     private void button3_Click(object sender, System.EventArgs e)
     { 

          this.Dispose(true);
          this.Close();

          this._parentForm.Visible = true; <--- did you previously instantiate a new object to have you form reappear???
          this._parentForm.Dispose(); 
          this._parentForm.Close();

     }

}

//in Home form
private void button3_Click(object sender, System.EventArgs e)
{
    EnggHome enggH = new EnggHome(this); <--- Notice the different constructor call.
    enggH.Show(); 
    this.Visible = false; 
}