CPS tried Singleton form in vb.net

We all get one object each time a constructor is called. If we call a class' constructor three times, we get three instances of the class. Also even if we don't write a constructor in our class, the VB.NET compiler creates a no-argument. However, if a class does have a constructor, whether it is a no-argument constructor or one that accepts arguments, the VB.NET compiler does not create a new one. Normally, these constructors have a public access modifier because they are meant to be invoked from outside of the class.
But sometimes there are cases where we want to limit the number of instances of a class to one. When we Press win+ R in windows XP ( I am using windows xp) it will display a RUN dialog. But when it loaded if we press Win + R button again and again we will get only one RUN dialog. How can we do this in vb.net? The Singleton pattern can be used for this purpose. This pattern is effective for limiting the maximum number of instances of a class to exactly one.

Imports System
Imports System.Windows.Forms
Imports System.ComponentModel

Public Class SingletonForm : Inherits Form

Private Shared myInstance As SingletonForm


#Region " Windows Form Designer generated code "

Private Sub New()
MyBase.New()
InitializeComponent()
End Sub

Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub

Me.Name = "SingletonForm"
Me.Text = " CPS Tried Singleton Form "
Me.Width = 450
Me.Height = 150
End Sub
#End Region


Protected Overrides Sub OnClosing (ByVal e As CancelEventArgs)
e.Cancel = True
Me.Hide()
End Sub

Public Shared Function GetInstance() As SingletonForm
If myInstance Is Nothing Then
myInstance = New SingletonForm
End If
Return myInstance
End Function
End Class


Using Sigleton form


Public Class UsingSingletonform
Inherits System.Windows.Forms.Form

Private Sub New()
MyBase.New()
InitializeComponent()
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim CPSsingleton As SingletonForm = SingletonForm.GetInstance()
CPSsingleton.Show()
End Sub

Public Shared Sub Main()
Application.Run(New UsingSingletonform)
End Sub
End Class