This is just off the top of my head and untested so use with caution on a copy. Obviously change the server addresses.
Code:
Sub changeLinks()
Dim ohl As Hyperlink
Dim osld As Slide
Const serverold As String = "http://www.technologytrish.co.uk"
Const servernew As String = "http://www.whatever.com"
For Each osld In ActivePresentation.Slides
For Each ohl In ActivePresentation.Slides(1).Hyperlinks
If ohl.Address Like serverold & "*" & ".pdf" Then
ohl.Address = Replace(ohl.Address, serverold, servernew)
End If
Next ohl
Next osld
End Sub
If you put all the files in a single folder it would be possible to adapt this to change all the presentations in one go. There is sample code on
www.pptfaq.com