Up until now, I've had absolutely no problem using Preview to open PDF files. But then all of a sudden today, no file will open with Preview. I downloaded a PDF and tried to open it, but nothing happened. I thought maybe there was something wrong with that file or maybe it didn't download correctly, so then I tried to open another PDF that had previously worked with Preview. In both cases, Preview started, but then nothing happened. With Preview as the main application, I brought my cursor up to the menu bar, and got the spinning beach ball of death. Right-clicking on the icon in the dock showed "Application Not Responding" and so I forced quit and tried again. Same thing each time. I tried deleting the preferences, but this didn't help, either. I tried to include the Apple report, but MacRumors won't let me post it because it's over the character count.