Screen Saver Programs

I asked a question a week ago and when I asked a follow-up question the expert never got back to me, so here we go again.

I would like to make screensvaer programs in visual basic. Actually I have made the programs. My original question was how do I get windows to recognise it and run it.

The answer that the other expert gave me was that I have to make another program that calls the EXE of the screensaver program and rename it's file extension .scr, I did this by creating the following:

Public Sub Main()
Dim returnvalue As Double
returnvalue = Shell("c:\windows\desktop\screensaver\GMscreensaver.EXE", 3)
AppActivate returnvalue
End
End Sub

I compiled the above and renamed it with the file extension of .scr and then placed it in my windows directory. I then went to windows properties dialogbox and selected this as my screensaver. The program did call the EXE listed in the sub main, but it didn't delay the 5 minutes that I have set in the windows property dialogbox. It just kept calling the program even after I closed it.

So I assume I have some code missing for the .scr program I wrote above. Or there is something else I am supposed to do.
What is the answer?