Turn the computer off, flip the bios switch to the setting where it will boot.
Turn the computer on.
Once on, flip the switch again. It is ok to flip while it is running.
Flash the bios back to stock and try to mod the bios again.
Same issue still even after flipping the bios switch. Fans on the Sapphire RX 570 aren't spinning and it's not being recognized by Windows 10.
Well, if you cannot get it to boot with a flip from BIOS switch I don't believe it's the BIOS that is causing that.
Once again:1) Turn off your PC
2) Switch to
UNMODDED BIOS
3) Boot your rig
Does your GPU show signs of life?
Yes) Congratz! No) Possible hardware problem, if under warranty return it