the hard drive on in my computer won't mount for some reason when i start up the installer from usb. that and for some reason the usb ports in the back won't work but i found a way around that. anyone know how i can get the hard drive to mount so i can format it and install? i didn't have this issue with installing nerish's yosimite distro so i've never seen this before. also just so everyone knows what process I'm using this is the guid I'm following. https://www.youtube.com/watch?v=tZ1byvvV3Ok&list=PL1Hand1aWK1RmK1CR5BEWQhksG9AGAvlX&index=1. got all the way to the point where I'm loading the installer from a flash drive. someone please help, i really want to go through with this!