Do you mean renaming the BIOS to the same name of the one downloadable from the official Asus website (being "P5Q-ASUS-1406.ROM")? Also: which version of AFUDOS do you suggest for the operation? There are so many ones...
A name like 1406.rom should be allright. But you say "a blank floppy". You do understand that you must boot from the floppy?