Sorry if this is a dumb question, but I have Adobe Acrobat 9.4.2 installed on my new iMac and cannot figure out how to USE it to open a PDF that is located online. I searched in Help for "opening PDF" and did not find anything relating to when the PDF is online. Every time I try to open an online PDF, the iMac uses Preview, not Adobe, which is a problem because some PDFs cannot be read in Preview. Related question: I sometimes write Word docs then convert them to PDF and post them online for others to read. How can I make sure my documents are readable to others using Preview? Appreciating all clues!