No idea why this happens, but it's happened a few times over the last few months.
Occasionally, and quite suddenly, the CPU just maxes out and the fans have to go into overdrive to cool it down.
On each occasion it's been kbd.exe and one of the svchost.exe's apparently fighting to see which one can use more cpu power than the other.
Stopping kbd.exe in task manager immediately cures the problem.
This process only controls keyboard shortcuts/actions, and the only thing I actually lose with it disabled, is visual info on the screen when I use a keyboard shortcut.
Trouble with disabling this, is my daughter has a habit of turning the volume way up to use the puny monitor speakers, and I plug my headphones in later and almost blow my eardrums apart.
Posting this really for info in case one of you guys gets the same symptoms, as I don't think there's a fix for it. However I would be happy to be contradicted on that.
I'm gonna look for a small volume control app (visible one), and disable this permanently.