Although I have installed Reader v8 and now v9 over the original v5 on my laptop, if I click on a PDF file link I still get the v5 logo page flash up on my screen. It then disappears of course, but then after a while the message "Could not find Acrobat External Window Handler" appears and the whole thing hangs. Somehow, a bit of v5 is still lurking and takes precedence over the newer one. How can I identify it and winkle it out? AR v9 works fine in itself.