freezingpickles :
My custom is almost done, but when I power it up there is this red light that briefly goes near the CPU, stays near the RAM for a few seconds, goes to the VGA for a few seconds, then stays at the BOOT_DEVICE_LED. Any help is appreciated.
The BOOT_DEVICE_LED is an indication that you either have a mis-connection to your HDD or SSD or there is no OS installed. Check that they are connected to the correct SATA ports.
To update your Bios, download the correct Bios 1902 file from ASUS support site to an empty USB stick formatted to FAT32.
Enter your Bios>Tools menu>EZ flash 3 utility.
Insert the USB and follow instructions on page 263 of your MB manual.
Hope this helps.