A while back i received a Toshiba P775-s5320 for free and wanted to install El Capitan on it. Made a bootable usb, slapped in the laptop, selected to boot for it. It booted into windows on the hard drive that is already in it. Tried to load the default bios settings, then choose to boot from the usb. Said that the media tes failed or something along that line.
I followed this guide right here https://www.youtube.com/watch?v=tZ1byvvV3Ok .
Now Im just looking for help with this problem and/ or an alternate guide to install El Capitan on this laptop.
You might want to install it in a VM first to see how well it'll work