Hey did you ever figure this out? I have the EXACT same issue, down to the mobo and keyboard model. Thanks man!
https://www.techpowerup.com/forums/threads/cant-enter-bios-of-my-new-gigabyte-z77x-d3h.196710/
https://www.techpowerup.com/forums/threads/cant-enter-bios-of-my-new-gigabyte-z77x-d3h.196710/