>>>>>I ran your program and it returns the correct association. Computer magic ?
>>>>>But I still get a "No association." error.
>>>>
>>>>When you right click on the .PPT file, what action verb is on the top of the shortcut menu? Try to run with default action
>>>>

>>>>*lnResult=ShellExecute(FindWindow( 0, _SCREEN.caption), "Open", tcDocument, "", "c:\temp\", 1)
>>>>lnResult=ShellExecute(0, "", tcDocument, "", "", 1)
>>>>

>>>
>>>"Show" I changed the "Open" to "Show" and BINGO!
>>
>>Did you test it with PowerPoint installed?
>
> Yes. And guess what - I get a "No association." error when PowerPoint is installed.
>If I change the "Show" back to "Open" on the PowerPoint machine the program runs again.

That's why I suggested to use default action

lnResult=ShellExecute(0, "", tcDocument, "", "", 1)