Turn off raid or ahci, only go sata , to load drivers you choose to setup manually choose the disk you want to format, choose load driver, make sure you download your drivers in extracted format onto a usb drive before you start and your done. I suspect you have raid or ahci in bios enabled.
Mobo not compatible with windows 8? Rofl, goes to show you how poorly educated the people that work for microsoft can be at lower levels. If it is using any mobo made within the past couple of years, you are good. Take his suggestion too ^