My wife and kids have all been bought e-readers. All were loaded with a book on someone elses PC. Now when I try to load on my home PC it says that they need to be de-authorised. Seems clear in the ereader instructions how you do that, but states that after going into my account, I simply follow the instructions to de-authorise. But there arent any bloody instructions to follow!!!!! This is driving me mad and they're all going to end up in the bin shortly. This is without doubt the worst, set of instructions (and worst website) I have ever seen. When I follow the instructions to check who the e-reader is authorised to, it says it's my wifes e-mail, but still won't let it load books from library to reader, on any of them. What a piece of cr*p.
When I finally sort this, do I need one account per reader, or can I run them all off one account, and just drop in books to each reader from one library.
I had exactly the same problem and it was driving me mad but finally got it sorted. Hopefully it will be of some assistance to you. I have a PRS-300 and I was advised to "hard reset the e-reader" the re-authorise. To do this:-
shut down device by going into settings and choosing 'shut down device'.
reset by pressing paperclip into small hole at bottom right of reader
turn on power switch then hold down 'arrow down' and '0' button at the same time (was given several other combinations before this one which may be specific to the PRS-300) as it opening up.
choose 'yes' to delete all contents
reconnect to the PC that you want to use and authorise as you would have done originally (that option will come up) and you should then be able to move books from your library to the e-reader.
This was from the Sony helpline so if this doesn't work try giving them a call.