I invite anyone else to confirm my take on this. I went through the tedium of changing storage modes on my 2011 build of a 2600K system. The Sandy Bridge system had been set up in RAID mode so that I could use ISRT "acceleration" or SSD-caching with the HDD boot-system disk. I had to change over to AHCI so that I could take advantage of Samsung's RAPID (RAM-caching) feature with an 840 Pro SSD.
As I recall, there are three storage modes configurable in BIOS:
AHCI
RAID
A legacy IDE mode
I also recall that making the conversion from one storage mode to another required that you enter BIOS immediately after any registry changes so that you could change to the appropriate mode for those changes, otherwise -- you might get a BSOD or most likely --the system wouldn't boot.
The problem you have is fixable. I'm just glad that I avoided it when I went through these troubles.
YOu still aren't entirely clear as to what you were doing. I assume you cloned your boot-system disk to the SSD? And then you installed the SSD in your system?
Anyone else? Comment?