I just added a 2nd hard drive in my computer and i went into bios just to see what the configuration is and its set to IDE. The options it gives me are IDE, RAID, and AHCI. Which of these should my configuration be set to?
Since you already have drives in a running system, you do not need to change anything in the bios other than perhaps enabling a sata port.
If the drive shows up in the bios boot screen, then all you need to do is go into disk management in windows and initialize the drive, then it will appear in the rest of windows (windows explorer, my computer,...).