Brian has the right of this. I haven't heard of anyone doing this, and I can't think of a way to do it either. Usually, when we present a solution that uses both the Laserfiche Client and WebLink, we talk about including one kind of link or the other in notifications and reports. Instead of using the Laserfiche Client, have you considered using Web Access? It might be easier to redirect to the appropriate location that way, since both WebLink and Web Access are web products (though it'd still require some work).

You could do this through VB Scripts

Option Explicit
DIM fso    
Set fso = CreateObject("Scripting.FileSystemObject")

If (fso.FileExists("C:\Program Files (x86)\Laserfiche\Client\LF.exe")) Then
  WScript.Echo("File exists!")
  ' Call client here
  WScript.Quit()
Else
  WScript.Echo("File does not exist!")
  ' Call Web Client here
End If

WScript.Quit()

You can also do the same type of thing with a .bat file

IF EXIST "C:\Program Files (x86)\Laserfiche\Client\LF.exe" (
        Call local LF client
    ) ELSE (
        Call Web Client
    )

Thanks for some great ideas. Bert, one of our experts says he might be able to work something out along the lines you suggest.