1) Your bootable CD is not so bootable. Try in another machine.
2) Your CDrom is not properly reading the CD. Try another CDrom.
I have xp pro and set it to boot from the cd-rom. When It starts to bootup at the bottom of the black screen it says boot from cd-rom with a flashing line after it. But it never boots from the cd-rom. So I tried my xp cd and it did the same thing with the exception that it said press any key to boot from cd-rom. The cd I am trying to boot from is an iso file. I got my comp. with xp pro loaded and the company doesn't know what the admin password is that they used. So I am trying a program to get it without having to reformat. Also I changed the boot sequence to cd-rom first already.