To avoid using the bios option to set boot from CD/DVD, or to help get incalcitrant bootable CDs or DVDs to boot, you can add Smart Boot Manager/MemDisk to your boot options in Grub and boot from Grub instead of using your bios.
You need a working grub loader installed.
First off, download these files attached:
then copy them to your boot directory:
then open up menu.lst in your editor (I have used nano here)
sudo cp memdisk sbm.bin /boot
and add this to the bootable options (not in the magic section)
sudo nano /boot/grub/menu.lst
Next time you reboot into grub, you will see a new entry "SBM-Boot a CD"
title=SBM-Boot a CD
With your CD/DVD in the drive, select this option, and you will get the Smart Boot Manager menu.
Scroll down to the CD-Rom option, press "Return", and then "Return" again out of the confirmation dialogs.
Your CD/DVD should now boot.
Tested on Ubuntu Edgy 6.10
Thanks to the Gentoo Wiki for guidance
Just retrace your steps to remove this option.