Hmm dragging and dropping on to the kindle?? hmm I dont know if you can do that....
Where are the books now?
I assume they are on your computer and showing in Calibre.
Connect your Kindle with the USB cable.
Then Do "Send to Device" [either with the toolbar button or Context menu] (to send the file from Calibre to your kindle)
Eject the kindle (Toolbar button) and unplug the USB
The books should show up in your in your kindle now.
|