I have windowns 8 and i was going to make a dual boot ok, then a saw some post on internet saying to disable secureboot first, so I did it, then i set the boot to usb, when I restart my computer there was a no operational system found i clicked some ESC and ENTER it just repeating, so a I pressed Ctrl + alt + del, it restarted the computer, but now when i turn my pc on there is a black screen wi