Ribbon Cable Connectors How Can I Add One More Hard Disk Drive To My PC?

How can I add one more hard disk drive to my PC? - ribbon cable connectors

I use a PC as a server for backups of my DVDs to play on my home entertainment. It has 80 GB and a 350GB hard drive already exists. I want to buy a 750 GB drive and just add that, if possible. Whoever had done this or I better change one of the smallest units. I prefer to retain the existing configuration and connect to the new drive, so good, but I thought I connectors for ribbon cable as I have two DVD players. Is it possible or desirable to buy an extension cord for a new unit of data and electricity? Thank you.