Linux accepts no input after booting.

I have just installed LinuxCNC on a new machine to use with my mill that I am converting, but when Linux has booted, either in graphic mode, or recovery console it accepts no keyboard or mouse input.
The boot menu accepts input with no problem, as does BIOS.
I have moved the keyboard and mouse to all 10 USB ports I could find with no result.
When the screensaver kicks in it does not switch off for keyboard or mouse input.
I have removed both PCI paralell ports and the PCI network card (Linux wouldn't see my onboard card) and it still does the same.
Main board is an Asus Prime H370M-Plus,
CPU is Intel, but I cannot remember which - can look it up if needed.
I would appreciate any input as this is very frustrating!
Peet.

Update:
I suspect a USB problem - when I move my keyboard / mouse receiver to any USB port it never gets a link, though a USB light is always powered, so it is not a power problem.
Moving the receiver to my laptop USB port, or before Linux has booted it gets a connection shortly after plugging in.

Are you using the Debian 7 (Wheezy) version of Linuxcnc?

Just a guess but, perhaps you need to have a newer OS to recognize your hardware?

I'm not a big fan of wireless keyboards or mice.

I am using linuxcnc-2.7-wheezy, which I thought was the latest?
I downloaded it towards the end of December.
I will try wired keyboard and mouse - I usually use a trackball and keyboard, both wired, for CNC, but as I am still just setting up I thought I would stick to cordless convenience for now.

I have now done further testing using a wired keyboard.
As soon as it gets past the boot menu, ie. I have accepted the boot, the NUM lock light goes off and I cannot get NUM or CAPS lock to function.
I have also found that pressing the power switch performs a normal power down, but on screen it ends saying power off, but the system stays running.

I would echo Todd here, I think your hardware is too new for Wheezy
You might try the Stretch test ISO:

www.linuxcnc.org/testing-stretch-rtpreempt/