I have a newly installed P8z68 and everything boots up fine. My question is regarding the post screen and a message that states "No hard disk drive is detected" then it flickers back to post and then boots to windows.
When i'm in windows I can see both my boot ssd, my storage ssd, and my storage HDD.
More about :asus p8z68 hard disk drive detected boots
In case you are still experiencing this problem, I believe that it has already been solved in this thread. Basically, you should disable the Marvell controller with an IDE setting in Advanced -> Onboard Device Configuration.