Does your BIOS support bootable CD ROMs? Bootable CD ROMs are also called "El Torito" CD ROMs, El Torito is the name of the specification for bootable CD ROMs. Computers made earlier than say 1995 or 1996 usually don't support El Torito mastered CD ROMs. If your system does not support El Torito mastered CD ROMs, you can create a PortaBoom boot floppy, and use it to boot your system. Part of the El Torito mastering process is to take a file that is a copy of a floppy disk, put it on the CD ROM in a certain place, and the computer (if it supports El Torito mastered CDs correctly) will boot itself with this floppy image from the CD when it starts up.
If your computer supports El Torito bootable CDs, is your computer set up to boot from the CD ROM drive? If it's not, you need to change the boot order in your computer's BIOS, so that the CD ROM is the device that is booted first if there is a bootable CD in the drive when the computer is powered up. If you don't have access to the BIOS, you may still be able to use the floppy image to boot the PortaBoom CD ROM, the floppy image will search all available CD ROM drives for an image when it is booted.