Ok i recently got new hard drive and battery for my macbook. I dont have the installation disk nor a working dvd/cd drive. but i do have leopard 10.6 an iso. on a usb 8gb hard drive. when i boot up computer it wont see that there is a usb drive there, i held down the option key too and still nothing. just a blank screen. I have no idea what else to do. Please help. thanks so much.