My first boot option in bios is flash drive, and windows 10 pro is on that flash drive. when I boot my computer it ends up at a flashing underscore. It says somewhere in the boot, "Can't find any device." I don't know if that is important. It always shows up directly before bios. I have a 760 gma. I have spent hours searching for solutions but I always hear that my problem is wrong usb port or my boot options are out of order. I have tried every usb port, and my bios are set with USB as the first option in bios. I thing I'm doing everything right. What am I doing wrong?