Yes, I'm using Windows XP SP2. And I said in my first post that I was using CDisplay. When I "Open With" CDisplay I just get a grey screen saying page 0/0 like nothing's there (and, as I said, many of these were completely functional at one time). "Then choose CDisplay as the program to open it with and make sure the radio is checked to always use this program to open files of this type." - What? I have Comic Book Archive files set to open with CDisplay, but what 'radio' are you talking about? And as for PDFs - most of these files were downloaded as CBR/CBZ - I didn't make them and, if I'm not mistaken, many of them aren't available in another format. And I don't know how to convert them to PDF, but wouldn't they have to be functional first? There has to be someone who knows what's causing this. I've had this happen to all sorts of Comic Book Archive files ever since I was aware of the format, so I doubt it's a rare problem and when I've deleted and gone back and re-downloaded the torrent or whatever it's been the same files that fail again, which also makes me doubt it's just my computer.