Well, I have almost finished assembling my new computer: all I need to do is install Ubuntu, download Wine, and I am pretty much done. Turns out the first step is harder than I initially thought, as my the computer cannot identify the Ubuntu Live CD.

There is no problem with which version of Ubuntu I am using, as I have tried both the 32-bit and 64-bit version of Desktop Ubuntu.
It's not the CD, as I have tried booting off of a USB as well as burning multiple CD's.
It's not the optical drive, as I have swapped it out and tried booting Ubuntu from another one.
It's not the boot order thing, as there is no other OS on any of the computer's parts.
It's not that I haven't burned a bootable CD, as the exact same CD succeeds to boot from my older computer (a laptop, mind that)
It's (probably) not the connections between the optical drive and the motherboard, as I have secured them pretty tight and triple-checked to make sure the right wires are plugged into the right slots.

The only possible thing that might cause the problem is that the computer cannot recognize the optical drive(s) for some reason. The proof that makes me suspicious is that when I go to the boot order menu in the BIOS settings, I only get two choices: the completely empty hard drive and a device named "IBA GE Slot 0400". The later might or might not be the firewire port option on my motherboard, though I suspect it is.

Anybody know what to do in this situation? Oh, and I am going to install Ubuntu for sure, as it is the easiest to use of all free OS's, and I neither want to spend a lot of money on Windows nor do I wish to pirate any OS for subtle reasons.

Sounds like you screwed up your IDE jumper settings. You know, the whole master, slave, master w/ slave thing - if thats set wrong things won't get detected right.

I agree with Kllrnohj. Where do you have the optical drive, on the same IDE chain as the master HDD or on a separate one?

While it could be that the drive is physically not set up right, it also could be that you just have to enable the drive in bios. In bios there should be a page where it lets you enable/disable/set up each of the ide drives. You may just need to enable the cdrom drive. Another possibility is that both the harddrive and the cdrom drive, if they are on the same ide chain, are set up (with the jumpers on the drives themselves) as the same (master, or slave.)

Another option is if the motherboard supports SATA and IDE, IDE might not be physically enabled, which is vaguely related to what lumberjack was saying.

Well, since the hard drive is SATA while the optical drive is IDE, I see no reason why I should have screwed up the master-slave setup. The optical drives are enabled in BIOS, btw, so there is no problem with that. After a bit of manual-reading and Google-searching, I discovered my suspicion was right: the motherboard cannot find the optical drive.

Also, I might be wrong about the fact that I booted off of a USB, as I might not have formatted the Flahs drive correctly...

Did you check that the IDE features are enabled? I have a bunch of mobos with BIOSes that default to SATA enabled, IDE disabled when cleared.

Yes, they are enabled, but it doesn't really matter now, as I got the problem fixed!

Turns out it was a combination of both a bad connection and a bad optical drive, as both of the optical drives I tried were bad (what are the chances of that? ). I swapped in a third one, secured the cables very tight, and the motherboard recognized it!

Thanks for the help, everyone!

Sounds like you never changed the jumpers on the CD-ROM drives to be set to Master without slave to me still

Sounds that way to me as well.