I am working on my dissertation and started to use some of my references previously stored as pdf files in/on my computer and pen drive backups. However, for every single pdf file, I now get this error message "adobe reader could not open file.pdf because it is either not a supported file type or because the file has been damaged " I have the following programs installed Adobe Digital Editions 3 Adobe Read XI plus various Shockwave Players I have uninstalled and reinstalled the programs to no avail. I have checked that .acsm file extensions are set to use Adobe Reader to open with, and have also tried to set that to Adobe Digital Editions (on someones suggestion), but no luck. This is disaster because I religiusly save all my pdf article and research documents, but now cannot use them for no apparent reason. Any help would be greatly appreciated.