Dell Precision T5500 Raid disks problem

Hi, I have a Dell Precision T5500. When I first installed the OS and the second drive I had no problem. When i tried put another SSD the raid controller started give me problems. I checked the bios and the RAID was set on "ON". I tried switching to "Autodetect / ATA" but when I restart the computer doesn't recognize any of my disks. Anyone know what can it be? Thanks