[1765chris]

I unplugged the keyboard from my PC whilst it was on, and it immediately shut down and now won't turn on, can anybody offer any help please?

 

[johnpost]

if the keyboard was a PS2 type you may have destroyed its ability to use
that jack.

if your machine has USB, then you could see if a USB keyboard works.
don't leave the other keyboard plugged in the PS2 jack when you try this.

 

[winbob]

Chris, if the machine does not even power-on...make any fan noises,etc, then plugging in a different KB or into a different KB socket will not bring you any Joy.

A PC will startup without a KB, but will POST a no KB error.

You apparently caused a Power spike internally when you "Yanked out the KB by the Jugular"

As a desperate attempt to restart things, I would simply try switching off the Power Supply toggle switch, and then back on again. Some units reset an internal breaker in this way. Good Luck!!