A Burning Question of Bootable CDs

Using Nero, I can make a bootable CD ,taking my Win98 Emergency floppy as the image, But here’s a question, ::: When you boot to the Win98 CD ( oem , Original of course ! ),
you get the initial message " boot from hard disk / boot from CD "
How is this done on the CD, where is the file on the cd…is it a bin file …or what…???
I would like to be able to edit the text message that appears upon booting…and alter the options…say i wanted to make a bootable CD with win98, winme , win2k , and some utilities on it…
Any help would be appreciated …or even some links to faq sites etc…
Thanks in advance

P.S…see the other post about telephone caller id