I am using the windows 7 on mine system and earlier that I have using the windows vista on mine system. I had no issue on mine system when I had the windows vista but after upgrading to windows 7 I have small issue eon mine system. My problem is that only some of the PDF files that I leave on my desk thumbnails. Others show the image only shows a generic Adobe logo and a red rectangle that says PDF. Can anyone suggest on this and so that I can solve mine issue.