OK first of all YOU MUST make sure the hard drive your trying to scan is not set as C drive.
But if not good then i can teach you how to do it look at picture:
1. Look behind your hard drive there should be pins behind it example
2. Look at the top of your hard drive there should be a jumper/pin instruction
3. There should be one for the option "Slave"
4. Match your jumpers/pins to the jumper/pin instruction
plug it in and reboot your comp, to check when your BIOS is loading it should say blah drive slave
Hope i helped =D