Your still not extracting the BOOTSECTOR... The bootsector is NOT a file in the cd fielsystem, rather info stored at the beginning of the CD, that allows it to be booted from. Try UltraISO and open up the ISO, it should say "Bootable" or something similiar, that means you can save the bootsector. So, from here click "bootable -> save bootfile" give it a name! From there, open the bootsector you saved in a hex editor, then make the changes to it as ncessary. Here's a screenshot of an ISO i opened up that contains a bootsector.