I have spent so much time on this and it is so frustrating! There are many other forums on the web with other frustrated customers/clients using different versions of Windows / AV and the same problem. I am using Windows 7, downloaded Adobe Reader X. The program installed fine. When I download pdfs from email, and then open them in Adobe X, everything is "a-okay." However, when I save a document from the internet and then download it from windows 7 (same procedure), I get the error message that the file is corrupted or damaged. EVERY SINGLE FILE FROM SEVERAL DIFFERENT STATE OR LEGAL WEBSITES that, also, previously opened fine in prior version of Adobe Reader. I have uninstalled, reinstalled, "repaired," uninstalled again with Norton & Window AV off and installed again ... still no luck. I depend on this Reader EVERYDAY!! I have seen numerous threads with this, BUT no solutions!! Please help!