If KindleGen doesn't work, I know why.
The following is from the KindleGen README file (as opposed to the IGNOREME file):
Download the KindleGen zip file from www.amazon.com/kindleformat/kindlegen to the desktop.
Right-click the zip file, select Extract All, and enter the folder name as c:\KindleGen.
100.5% of KindleGen problems are rooted in those two lines of instructions. So let’s pretend we work for KDP and have to hyperbolically re-frame these instructions seventy times a day over the phone to irate authors:
Go to this KindleGen page. (Don't be a yutz. Use your center mouse wheel to open the link in a new tab.)
Download the KindleGen.zip file TO YOUR DESKTOP. For the love of all that’s holy, do not improvise. Download that file TO. YOUR. DESKTOP.
Go to your desktop. Not the one your keyboard is sitting on. The desktop on your computer monitor, where the icons live.
Right-click (with your mouse) on the kindlegen_win32_v*_*.zip folder icon.
Select “Extract All” from the pop-up list.
DO NOT AUTOMATICALLY CLICK OK OR EXTRACT once the Extract All pane opens.
Manually alter the destination folder to c:\KindleGen. No, this folder cannot be located via ‘browse’. c:\KindleGen must be typed into the field that way, exactly as it appears. (see Exhibit B below)
Pay attention to the CAPITAL LETTERS, people. They matter. K. G. (Why oh why couldn’t I have gone to clown college like the cool kids?)
Pay attention to the SLASHMARK DIRECTION. It’s the one above the enter key, not below it. (Dear God, I need a shot of Jack Daniels. Straight-up before I’m toe-up.)
Click OK.
Exhibit A: This is what the Extract Pane looks like by default. DO NOT automatically click Extract.
Exhibit B: Instead, clear out all the blue stuff pictured above and type c:\KindleGen in the folder field, like so, and THEN click Extract:
All better. It probably seems like nothing happened once you clicked Extract, but have faith. KindleGen does its job quietly in the background.