Msi Z68 GD65 G3 bios 23.7 no signal video AMD 7970 and flash bios 25.6 problem

I had to update the bios 23.7 to 25.6 because the graphics card was no video signal.

I have a i5 2500k sandy but with the new bios overclocking has me down and is more unstable.

If I go back to the old bios chance that I will have the video signal Asus...