On Windows, why does Writers Café not always find Adobe Acrobat Reader?
Sometimes there is a problem with the PDF file association, resulting in advice from Writer’s Café, despite the fact that Reader is installed on your system and PDF files can be launched from Explorer. This is caused by the absence of certain registry keys and can usually be fixed by re-installing Acrobat Reader. If the problem persists, you can still read the PDF files by locating them on your system either from within Explorer or from the Reader file dialog.