If you have a z77 Extreme4, the memory support list is at ASRock > Z77 Extreme4 Memory Support List
Is this a new build?
Have you tried booting into the bios with only one memory module installed?
Have you tried clearing the CMOS?
You will save a lot of time if you provide a detailed hardware list.
We can best help you after you create a detailed hardware list in the System Specs portion of your
forum profile http://forums.tweaktown.com/profile.php?do=editprofile at the bottom of the
profile page or in your forum signature http://forums.tweaktown.com/profile....=editsignature.
Be sure to include brand names and model numbers.