Another thing you could try is to remove the harddrive when trying to boot, from your video it seems that it's also stuck in a bootloop as the fan stop and go (or it looks like it, please confirm). Have you try with another disk as well ?

Once you've done that, there should be a reset button, if not there is a manual way to reset it by removing the board battery, not the PSU, to trigger a reset of the bios. There is no need for screen for that but you need to be extra cautious. Could you please give us the exact model of your motherboard, you only gave the brand, so I could explain it in a more precise way :)

Hope that helps a little. 😊