Tower Plus EBT2250, switch from a raid to achi configuration

i have a dell ebt 2250 and just 1 ssd drive but dell sent it to me using raid set up. i want to oly use achi since i will never have to drives in it. when i go into bios and switch it to achi when booting up doesn' see hard drive. do i have to do a clean install so achi drivers load?