Executes other form periodically - vb.net

Question

In Vb.net, I want to show my main form and other form periodically.
The last form does check operations and automatically closes.
Should be implementing threads, but I am not sure if it's possible...
My code is empty..
Imports System
Imports System.Windows.Forms
Friend NotInheritable Class Program
Private Sub New()
End Sub
<STAThread() _
Shared Sub Main()
Application.EnableVisualStyles()
Application.SetCompatibleTextRenderingDefault(false)
Application.Run (New formMain()) '--> Main Form
'All code here is not execute until Main Form is closed
End Sub
End Class
Thanks in advance.
Edit: Sorry, I am a newbie in vb.net, I would want to say show my main form.
Edit 2: I think I didn't explain well, but with the help of #JeremyThompson I can complete my code.
FormMain: Now, When I try to close this form, I show another form to do check operations but I hold this (FormMain) always visible.
Private Sub FormMain_FormClosing(sender as Object, e as FormClosingEventArgs) _
Handles FormMain.FormClosing
Me.Visible = True
Dim anotherForm as New CheckOperationsForm()
anotherForm.Show()
e.Cancel = True
End Sub
Other form (or FormCheckOperations()): When the routine coded in this form is completed I establish the value of a boolean _successfulChecking, so if this boolean is true, main form keeps on showing, in another case, the application ends.
Private Sub FormCheckOperations_FormClosing(sender as Object, e as FormClosingEventArgs) _
Handles FormCheckOperations.FormClosing
If Not _succesfulChecking Then
End 'Close application
End If
End Sub
My doubt is, how I can show FormCheckOperation periodically from MainForm (I could call FormMain.Close() to do it) or how do it from Main Sub?
Edit 3: Now, In my current approach, I open 2 threads in Main Sub, the first one with the Main Form and the second one with another thread which opens CheckOperations Forms each 60 seconds. But when executes in Visual Studio, forms stay "behind" of the SDK, furthermore, they are not working properly, but I think the final way should be closer.
Imports System
Imports System.Windows.Forms
Friend NotInheritable Class Program
Private Sub New()
End Sub
<STAThread() _
Shared Sub Main()
Application.EnableVisualStyles()
Application.SetCompatibleTextRenderingDefault(false)
Dim threadFormMain As New Thread (AddressOf launchFrmMain)
Dim threadFormCheckOperations As New Thread (AddressOf launchThreadFrmCheckOperations)
threadFormMain.Start()
threadFormCheckOperations.Start()
End Sub
Public Shared Sub launchFrmMain()
Application.Run(New FormMain()
End Sub
Public Shared Sub launchThreadFrmCheckOperations()
While(True)
Dim threadForm As New Thread(AddressOf launchFrmCheckOperations)
threadForm.Start()
'Here I should stop while loop during 60 secs…
'Thread.Sleep(60000)
End While
End Sub
Public Shared Sub launchFrmCheckOperations()
Application.Run(New FormCheckOperations()
End Sub
End Class

Answer 1

In the FormMain_Closing event, set Visible = False, instantiate and show another form and set e.cancel = True, then put code in the anotherform's closing event to End the application.
eg:
Private Sub FormMain_FormClosing(sender as Object, e as FormClosingEventArgs) _
Handles FormMain.FormClosing
Me.Visible = False
Dim anotherForm as New AnotherForm()
anotherForm.Show()
e.Cancel = True
End Sub

Answer 2

Finally I solved this.
In Main Sub firstly launches a thread with check operation forms (globally declared) and later launches mainForm in main thread.
The thread with check operations contains while loop which creates a new thread in each iteration, but with Thread.Join() stays waiting the end of previous thread, so it avoids to create other thread while there is a thread opened.
The code is the following:
Imports System
Imports System.Windows.Forms
Friend NotInheritable Class Program
Private Sub New()
End Sub
<STAThread() _
Shared Sub Main()
Application.EnableVisualStyles()
Application.SetCompatibleTextRenderingDefault(false)
threadFormCheckOperations.Start()
Application.Run(New FormMain())
End Sub
Public Shared threadFormCheckOperations As New Thread(AddressOf launchThreadFrmCheckOperations)
Public Shared Sub launchThreadFrmCheckOperations()
While(True)
Dim threadForm As New Thread(AddressOf launchFrmCheckOperations)
threadForm.Start()
threadForm.Join() '---> Wait until thread is closed
Thread.Sleep(60000)
End While
End Sub
Public Shared Sub launchFrmCheckOperations()
Application.Run(New FormCheckOperations()
End Sub
End Class