Hello sophiehall,
You only need to authorise your Reader if you buy a copy-protected eBook (like if you buy something from Smiths or Waterstones as you mention). So, if you visit one of these stores via the link in the left hand column and buy an eBook, once you get to the part on the bookstore's website after you've paid and they give you a button to press to download your eBook, this is what you need to do - and it seemed to work for me!
I have two top tips by the way - 1. some of the bookstores (like Waterstones) have a prompt next to the download button saying that you need to download Adobe Digital Editions if this is your first eBook purchase - DON'T!!! The Sony Library software does this job for you - just go ahead and download the eBook - at which point you will be asked whether you want to 'open' or 'save' the eBook. Top tip no.2 - always press 'open'!
If you do this then you will automatically get an on screen prompt to authorise your computer (with an Adobe ID and password). If you don't already have one (which I guess you won't yet) there's a 'get an Adobe ID' button. Press this and you'll be redirected to register with Adobe - remember the username and password you choose here and once finished go back to the box and enter these and hey presto your computer will be authorised and your eBook purchase will appear in your Library!
When you drag and drop your eBook onto the Reader itself, you will get a similar box to before asking you to authorise the Reader now. Use the same ID and password (although you may not be asked for them again as it seems to automatically use the same one as you used for your computer) and your Reader will be authorised and the eBook will be on your Reader.
I'm not sure how many Readers you can authorise onto one computer, but I think I've read somewhere that it's around 5. My wife and I both have a Reader(!) and both are registered to our PC with no problems - just make sure you use the same Adobe ID and password each time.
Hope this all helps!! Good luck!
