Apart from doing what the others have suggested, at the very right hand side of Calibre is a list which says Authors, Formats, (should show Mobi or azw, and possibly some others as well. Path (click to open). Clicking on this will take you to the file where the book has been saved. Clicking on that should open the book in Kindle format (assuming that you saved it in the correct Format and you have Kindle for pc on your pc (can upload it direct from Amazon if you don't have it). I
f you can't find it on Amazon, there is a link to it on my website.