I received an e-mail with a PDF attached; when I click on it, it opens briefly to show a legitimate page, then "dissolves" into total black and I can't get pages to show again. I have an i-mac running OSX-5 without intel. It seems this happened after I upgraded; since I could not locate system requirements, I assumed that the automatic notification made the automatic download "safe". Would really like to view the attachment on this computer. Also, the PDF switches to Safari rather than Adobe to open the document. In fact, I notice that as I write, this is in Safari, rather than the Adobe Web site where I started. Perhaps someone can help me clean up my operation. Should I trash the Adobe presently running and go to a lower number? I currently am using Adobe 9. I am also not particularly computer smart, so please be patient with me.