Mateo should click on help.
What is the use for the secondary hard drive?
If it is to run another operating system, such as a Linux flavour or another version of Windows, you would need to:
1) correctly format your drive
2) Install your OS
If you are using the HDD alongside your current OS, you need to:
1) Lower the boot priority of that drive in your BIOS
2) Format your hdd for use in your OS.
(Use NTFS for Windows and HFS+ for OS X)
