Updating bios in gigabyte ga 970a d3 xmlvalidatingreader is obsolete

After pressing reset power buttons together for ten seconds MOBO is booting old backup bios, and after few seconds I can see the message: "Warning: MAIN BIOS CHECKSUM ERROR! Everything works fine with stock F7 version, system is booting without any problems, memory oc to 1600MHz works fine.

My configuration: Gigabyte GA-970A-D3Phenom II x4 945 3GHz2x 4gb Corsair 1600 DDR3 ram Gigabyte Ge Force 660Corsair SATA SSD 120 GB drive Chieftec 550 W PSUI tried few bios versions from gigabyte's official site, downloading from different servers, also once from @bios application F10 version of bios, all with the same result as I've stated before.

Now I have had Problems with Portal 2 on my Old Laptop, e.g. It was a successful install (or so it say's) and I thought it would be ready to play.

I entered the game and it crashed, and gave me the BSOD.

The motherboard also offers 4x 1.5V DDR3 DIMM socket that supports memory up to 32 GB.