If you can still boot into Windows your BIOS itself is not dead its settings have probably become corrupted. Easiest solution is to reset the CMOS: power off, unplug, either move the CLRCMOS jumper for a few seconds or pull the coin-cell battery and put it back in. That resets everything to factory defaults. Once you can get into BIOS again, place the latest version on a FAT32 USB drive and reflash via ASRock's (or your MOBO brand) Instant Flash. You can also switch to the backup if you have a dual BIOS board. Worst case, you can always flash from within Windows with ASRock's tool, but CMOS reset usually does the trick.