I just spent the last hour and a half dealing with the same problem (couldn't get my laptop to recognize the Cybook). Thought I'd just post that after trying all the ports, plugging and unplugging everything, booting and rebooting everything in various combinations, the Cybook finally popped on. Jeepers! I quickly transferred some books
after first copying the system file to my computer -- now I have things to read if this happens again! My advice if you have this problem -- be persistent!