Hello, apologies if this has been done but every time I flick the back key the PC wipes all the threads I just looked at.

Im using a PRS-300, and over the last couple of years have merrily downloaded from Waterstone with no problem.  I am now trying to buy Epub books from other retailers.  I have downloaded one (definitely epub format) which has appeared in my library software (ie the sony library software that came with the ereader).  So far so blah.  However, this time when I try to transfer to the ereader, I just get the circular status bar (equivalent of rotating hourglass).  There is no error message, it just stays like that until I turn off the pc.  Currently been going just over a hlaf hour. 

Im using windows 7, file size for this book is 1.3mb, I have latest Adbode Digital editions and I just successfully bought and donwlaoded a book from waterstones (Im not for or against them, I just know their stuff works so used that as a test).

Any ideas as to whats gone wrong please?