There is a blue cord that connects to the factory hard drive, and a black, orange, red, and white cord that connects to it. My question is what is the blue cord for, since it only connects to one hard drive. The other cord can connect up to two hard drives, but the blue cord only connects to one.
Nelson: that is a standard Sata cable (data cable), unlike the old IDE they only have 1 connection.
you would need another Sata cable (there pretty cheap, usually red, get an angled one so it fit's better)
the sata cable will connect to the Sata HDD and then to the motherboards Sata slot. there should be 4 (usually minimum, sometimes there are only 2).
the Sata connection on the motherboard is usually bottom right, so have a look there if you can see the cable connected there.
You can't get a Sata cable with multiple connections, they only come with 1 connection.
Make sure your mother board has an unused sata connection before buying a sata drive, or if it has an ide connection you could get an ide drive.
Hi adding another drive is not an issue these days as SATA is how it is done. so it can be internal or external with a case or not.
The blue cord is your data connection for the hard drive. The multi-wire cord is your power connection, and yes, it can be used for 2 hard drives (devices).
Dont worry about the blue one, its for the first hardrive to load the OS on boot. Connect only the black one