Please make sure the SATA mode in BIOS is set to "RAID". This may vary depending on your motherboard manufacturer. Then Check the current status of the disks array. Do they show up as "degraded" or "non-raid" Normally, on Intel® boards you could access the iRST by pressing CTRL+I at the POST screen on your computer. This process may be different on Gigabyte* Boards.
You could try this third parties software on your own risk RAID 5 Recovery - FreeRaidRecovery.com
However, since the content in the RAID is important, another option will be to take the computer to an authorized RAID Data Recovery - Data Recover Center in order to safely recover the required information.
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