Checking if program is already open

I have found another problem in a small app I have written. I need to check if an instance of the program is already open before it opens a second copy. If it is already open, I want to stop the second copy from loading. Does anybody know the procedure for detecting a loaded version of the program?

Cheers,
Russ

Code:

---

' See if there is already and instance.
    If App.PrevInstance Then
 ' Activate the previous instance
        AppActivate App.Title
       
' Terminate the new instance
        Unload Me
    End If

---

Hi,
(working with Russ on this one!).
The app's previous instance is hidden. We have got it now so that it doesn't load up a second version (thanks, HeSaidJoe), but how do we get the original one to show again when a user tries to load a second one. AppActivate just doesn't seem to be working!

Any ideas

Cheers

Shaun