I'm at a loss. I read your manual and everything you did is right. You just may need to keep a ps2 keyboard on hand. If the mb is new you may want to RMA it. Sorry.
I don't think that it is the motherboard's problem because it recognizes the usb mouse and the keyboard is not a brand gaming like the mouse.i will test another usb keyboard on and i hope that it is the keyboard and not a problem on the MOBO,otherwise i will try to reset BIOS with the CMOS battery technique.