I'm having trouble getting my computer to recognize the fifth drive I have just installed. I have 4 SATA connectors and 4 Raid SATA connectors on the ASUS Motherboard. The fifth drive is connected to one of the Raid SATA connectors and isn't recognized, How come?

Did you enable the 2nd controller in the BIOS? Also while you're at it, can you post your ASUS MB model?