Fresh AsteriskNOW install will not boot

i download the 64bit AsteriskNOW 10.13.16-17 iso and installed that on a 4GB flash drive with rufus 2.15.
I booted that on a core i5 pc with a brand-new samsung 250GB evo 850 SSD. It booted fine and then stared Schmooze. It asked a much of questions, nothing weird and the install appeared to go ok. However, upon reboot the PC says the SSD is not bootable! I tried this twice with the same result. Anyone know what to do next?