3 hard drives?

I'll bet this is a REALLY stupid question, but take it easy on me plz, I'm kind of n00bish as far as computers.

I currently have two Hard Drives and one DVD-RW drive, leaving one empty slot (slave) on the drive cable.  I'd like to mount a third hard drive, and want to know if I could just slave it to the DVD-RW drive O_o If not, how would I go about mounting my third HD?  Once again, apologies if this is an idiotic question, but I've never had more than 2 HD's at once, nor known anyone who has that I could ask.

I slave my backup drive onto my CD drive.

I can't say whether it will default you to the CD drive's ATA speed, but it works. Try setting it for master, in the least.

Thanks!  Just out of curiosity though, how would I mount a third HD with two optical drives?

>>3
1. Buy another IDE card.
2. Buy a USB hard drive/CD drive
3. Buy a firewire hard drive/CD drive
4. Buy a SCSI hard drive/CD drive
5. etc.