Hmm strange,
When it does go black, you can press Ctrl+Alt+Del
That will restart the booting process instead of having to reboot the entire device.
It's strange that you can't access the bios settings, so it seems you've wiped the OS.
If you can access the config try reseting everything to default and then boot off the USB, make sure the USB is priority and that their is nothing but the OS on the flash drive.
Another thing could be a faulty USB or you've bricked the motherboard...
But goodluck If you still need help I'll try my best to help. :)