E521 won't boot from CD

I'm in the process of adding a second hard drive to my Dimension E521. Whenever I try to boot from CD-ROM I get this message.

CD-ROM Device Driver for IDE/ATAPI, Ver. 1.5 rev.016

 

**Error: No CD-ROM drive found, please check power or cable.

**Error: IDE CD-ROM device driver NOT installed.

 

Driver not found:  'generic'

 

A:\NWCDEX.EXE requires a Driver name to be specified.

Invalid drive specified

Command or filename not recognized 

Command or filename not recognized

Command or filename not recognized

Command or filename not recognized

A:\> 

 

This is puzzling since my system doesn't have an A: drive, nor does it have IDE. It's all SATA. I have two optical drives. Both work fine in Windows and are recognized by the BIOS but neither will boot.

The only thing I can think of is that the drives are numbered in an unconventional way. The manual recommends using SATA-0 and SATA-1 for hard drives, SATA-2 and SATA-3 for optical drives. Currently my system looks like this:

SATA-0  80GB HDD

SATA-1  CD-RW/DVD-ROM drive

[both exactly where they were when I received the computer from Dell]

SATA-2  DVD-RW drive (installed by me)

SATA-3  500GB HDD (just put in, will soon be the boot drive)

The 80GB drive will stay on as slave. Would it be worth my while to rearrange these to the 'correct' order?