on the newer efi mb check under boot devices. make sure the cd-rom and ssd are shown. most mb now will show efi cd-rom and non efi cd-rom. you may have to put the non efi cd-rom as the first boot device. if that wont work most mb if you hit f8 bring a boot manager up you can then selet cd-rom or usb stick. you need to have the disk and or usb conected before you hit f8.