I had exactly the same problem with a 3 disks Raid 5 (2 was as non raid after a bios reset)
The solution I choose (as testdisk crash on 7) is to put all the 3 disks to non raid and recreate exactly the same raid system.
When I boot again after that process. The disk go to initialize. 5 days long...
Now it's finish but I have to "initialize disk" (windows speaking : GPT or MBR) as I cannot see it. I really don't think it's good idea ?
How I can do to get back my files ? Can I set up GPT partition to read it ? How can I know that I don't already erase everything during initialize step ?
Config :msi P67A-GD65(MS-7685)Chipset P67Processeur Intel Core i7-2600KRAM DD32600G DD3-1333(667 Mhz)