Asus p8z68-v pro no hard disk detected

Try moving the HDD to a SATA II port.

I have a similar system and it said the same thing regards to the HDD
p8z68 deluxe
16gb corsair vengeance
I plugged my HDD into the Marvell (Navy Blue) sata port using the provided 6gb cable and the no physical disk message went away. Being that my OS drive is mechanical it's top transfer rate is still 3gb in that port, and I have had no OS loading/running issues to date (Win 7 - 64 bit). I am still learning about my new mobo and setup in general but when I had the HDD plugged into the normal usb 2.0 com port I would see the safely eject device icon in the sys tray. I believe that is because those ports are "hot swappable" as referenced in the user manual and in the bios advanced menu. Not sure about your keyboard problem though. I would have thought that the system would have auto installed any drivers required for the ps2 connection port. You could try booting from the motherboard support CD and just looking through it to see if there are any drivers there that would be of benefit for the ps2 port.
Hope this helps some...