BIOS won't let me boot from CD

I just bought an older computer with Windows 2000 Professional on it. It works fine, but right now I'm trying to install Windows 98 SE on it. I'm extremely frustrated, because I'm trying to boot from the CD drive, but the boot priorities don't work. I've partially deleted some of the C:\ contents already, because I want to do nothing but install Windows 98. It's an Award Modular Bios 6.00 from 2000, but when I enter setup and go into the Advanced Bios Features, the boot priorities do nothing. I'm trying to boot directly from the CD drive, but I have 2: One is a reader and one is a writer. I've tried setting all 3 of the booting options to "CDROM", but it still boots from the hard drive. How on earth do I get it to boot from my Windows 98 CD? Please help me.