I was just about to add another hard drive, but the gray cable in the computer is already plugged into the CD-ROM and the main HD. Is there another cable I can buy which would plug into one of the main cable ends and then split off into two, so I can have a CD-ROM, and two HDs? Like the 'Y power cords'?
Most motherboards have two ide channels, both capable of supporting two devices.. check your motherboard manual, more than likely you have another ide connector and just need another cable..
IDE Cables can only have two devices on them at any one time. If your computer is a more modern unit, there should be a second place on the motherboard to plug in an IDE cable. You should check the jumper settings on your CD-ROM and plug in a second IDE cable to the place on the motherboard (Usually right next to where the first one is connected) and set the CD-ROM as master on the second IDE connection. Then you can plug the new hard drive to where the CD-ROM was, making sure to set the new drive as a slave unit.