Did this system ever boot or is it a new install?
The error you are getting does not likely have anything to do with a password but improperly configured bootloader. The link below is another to configuring Grub2, specific to Fedora.
Posting more detailed information would be helpful. Boot any Linux Live CD, go to the site below and run the bootinfoscript. It will produce a results.txt file which you can post here and get some help. There is a link to specific instructions on the page.