The newest of computers often don’t even have an extra IDE port for you to connect to. I just ran into a Dell that I had no way to hook up the hard drive from the old computer to. This, of course, made transferring the files from the old computer to the new that much more difficult.
The best way to attach a regular 3.5″ IDE hard drive to an SATA only computer or laptop is to use an external case with either a USB 2.0 or FireWire (IEEE 1394) connection.
Here’s a link to a decent one on Amazon: Sabrent Ultra Slim 2.5-Inch SATA to USB 2.0 External Aluminum Hard Drive Enclosure EC-UK25 (Black)