Hello laptop70,
I think your problem lies with having downloaded Adobe Digital Editions from Waterstones. The Sony Reader Library software encompasses Adobe Digital Editions already so you don't need to download it separately.
However as it sounds like you have downloaded ADE, you have two choices. If you leave things as they are, it's just that you have to use both ADE and the Sony Reader Library software to manage your copy-protected eBooks. In practical terms this means that you have to manually import any books that you buy into Reader Library.
You do this in Reader Library by pressing 'File' and choose 'Import Files' from the drop down menu. You then need to navigate to the folder 'My Digital Editions' which you will find in 'Documents' or 'My Documents' depending on what version of Windows you have (I'm assuming you are using Windows!). In the My Digital Editions' folder you'll find your eBook to import - you do this by selecting the one you want and press 'Open'. This eBook will appear in the Library section of the Reader Library software and you can then transfer it to your Reader by dragging and dropping.
The second option is a bit more involved but once done makes the process a bit easier going forward. You can uninstall Adobe Digital Editions so that you only have to use Reader Library. To uninstall ADE: from the 'Start' menu of your PC, under 'All Programs' you should find a folder called 'Adobe'. If you click into this and find sub-folders for Adobe Digital Editions, you should find an option to uninstall which you simply click. However, to ensure you can now use Reader Library effectively, you need to take one additional important step (otherwise Windows will not recognise your eBook files because it associated them with ADE which you have just uninstalled!) So, connect your PRS350 to your PC. Go to the 'SETTING' drive on the Reader (you can find this under 'Computer' or 'My Computer') and open it. Then double click the 'Setup Reader Library' icon. You should then get an on-screen prompt saying that some files are not associated with Reader Library and do you want to associate them now. Say yes. You're done - the next time you buy an eBook from Waterstones or somewhere similar - when you download the book (pressing 'open' when prompted) the book will transfer straight to Reader Library ready for you to drag and drop to your Reader.
You can check eBooks have transferred successfully by the way by clicking on the 'Status' icon in the left hand menu in Reader Library - saves waiting around as you don't get a message to say when the transfer is complete (although the transfer should only take a matter of seconds).
Hope you get on OK.
I downloaded from Sony website several books no problem. I then went to Waterstones. they downloaded adobe digital. I downloaded a book.I had problem downloading ( drag & drop ) to reader it went on synchronising 4 hours until bedtime when I had to disconnect. was told task was not complete I disconnected. Next day the book was on reader 3 copies.I have tried downloading since with same result.I am doing everything the same as first time. help please. Just to clarify arrows going round and round in circle. suggestions please. p.s I love the reader
