I've been playing around with the Kindle for PC program and came across something interesting. If you have the book saved on both your Kindle and Kindle for PC you can access your notes by copying the MPB file from your device to the folder you have linked with your Kindle for PC. There you can look at and edit your notes. At that point, you can copy them back to the device. I would suggest using a backup of your MPB file to avoid any accidental erasing of the information.

FH