Can you boot into the BIOS? If you can double check the boot order, if you use SSD, make sure the storage mode is in AHCI mode, also make sure the boot device is connected into the 1st SATA port.
Or if you can't boot into the BIOS, the BIOS update is not good. Then check the asus support: Solution-BIOS fails to update https://www.asus.com/support/FAQ/1029957/