[decemberchups]

I got a Kindle Paperwhite because I was told it would be easy to download my kindle books to my computer, transfer to the kindle via USB, transfer to calibre, then calibre would be able to convert them to other formats. After many hours, I got it to work: installed all the plugins, added my kindle serial number, etc, conversion successful! It was working last night.
Now, I am on a different laptop, Same Windows OS, same versions of Calibre, same procedures as yesterday, and calibre is saying the books are locked by DRM. What am I doing wrong here? This is so frustrating. Thank you in advance.