Certain distros not booting?

[Cole Tuininga]

Hi all - I have a little bit of an odd situation I was hoping somebody
might be able to shed some light on.

Somebody has asked me to take a machine with a 300+GB hard drive, and
install 5 or 6 different distributions of linux on it for them.  The
idea is that they want to play with the different version for a while
before picking one.

The hard drive is the master on IDE0, and the CD drive is the master on
IDE1.

Here's the odd part.

Certain distributions' install CDs won't boot.  I can boot Ubuntu (both
live and install CDs), I can boot Knoppix, but I cannot boot either
Fedora Core 4 or CentOS 4.1.  When I put them in, the boot process just
acts as though there isn't even a CD in the drive.  

I'm reasonably certain that both CDs are good - I used them just a
couple days ago.  

It's not boot order in the BIOS - I have that set to use the CD drive
first.

Anybody have any thoughts?  I'm more than happy to provide any required
information that I didn't post here...

-- 
"Maybe I'll be able to get a job when I graduate..."
 -Linus Torvalds

Cole Tuininga
Lead Developer
Code Energy, Inc
colet at code-energy.com
PGP Key ID: 0x43E5755D