Can you kill a motherboard with a bad keyboard?

I mistakenly plugged in an PS2 keyboard that I had cleaned and was probably not quite dried out yet. The computer never booted again after that, not even a post screen. I checked the power supply and it's fine. My question is, is it possible to kill a motherboard (7 or 8 years old) with a bad/wet/shorted PS2 keyboard? Or is this just bad luck? The system had been showing some occasional BSODs before this happened so I am not sure if it was bad luck or the keyboard.