Lost data on primary drive when changing SATA configuration in BIOS to RAID (from AHCI)

I have done the mistake of changing the SATA Configuration in BIOS to RAID. I had a perfectly working Windows 7 Ultimate environment (running on 3TB disk - GPT partitioned into 1TB and 2TB space) on a custom built machine (ASUS RAMPAGE IV EXTREMRE motherboard with Intel 3960K I7 processor, 32 GB RAM). Added 2 3TB disks and thought of doing RAID 1. It warned that OS reinstall will be needed and I thought that it was for the two new 3TB disks. Anyways, I rebooted and Intel RAID configuration menu came up asking me to choose the type of RAID configuration and disks. I chose the two news 3TB drives as member and the existing drive as non-member. Now it rebooted and asked me to insert the Windows OS CD. Since I could not locate the installation disks unfortunately, I decided to do that later. I went back into BIOS and changed the SATA configuration to AHCI. But to my surprise, I could not go back to original configuration and now I can not access my drive. It is not recognizing the drive any more…seems like my process did something and I lost everything. Is there any hope of recovery ? I had some important stuff that I did not take the backup off.

@ AnilBostonian:
Welcome at Win-RAID Forum!

It is the track zero of the HDD with its new RAID partition table, which prevents, that the OS can see the data, which had been stored in AHCI mode.
This is what I would try to do:

  1. Boot and enter the RAID Utility.
  2. Delete the RAID array you have created by mistake.
  3. Reboot, enter the BIOS and set the SATA Controller to “AHCI”.
  4. Reboot and look, if the OS can see the data of the HDD, which has been member of a RAID array.
  5. If the OS should not detect the data, you may try to run a Data Recovery tool.

Good luck!
Fernando