you can convert a HD disk to DD by taping over the hole (not the sliding protection hole but the fixed hole on the other side) and formatting in the KN2000. Since you have described saving and then loading from the KN2000 to disk in your post you have already proved there is nothing wrong with the disk drive or KN2000, the problem is with file format or more likely the copy. If copying genuine KN2000 format files (double check this) to the root of a DD KN2000 formatted floppy does not work, then it is possible the pc floppy drive or windows is too modern and you may need a win98 era machine (for both windows and floppy drive) or possibly try the copy in dos.