add button to all last slides?

[Geoff Cox]

Hello,

I wish to add an action button to each of the last slides in a series
of ppt files.

Have found following on Steve Rindsberg's site which will add a
selected action button all the slides in a presentation

Sub SuperDuper()

Dim oSh as Shape
Dim x as Long

Set oSh=ActiveWindow.Selection.ShapeRange(1)
oSh.Copy

For x = 2 to ActivePresentation.Slides.Count
ActivePresentation.Slides(x).Shapes.Paste
Next

End Sub

How do I change this so that an action button which links to a
particular ppt file, is added to the last slide of all the ppt files
in a folder?

Any ideas appreciated!

Cheers

Geoff