It sounds like you may have a short in the keyboard (if touching the light on the keyboard solved the rebooting problem). While shorts are not unheard of, I can't actually say that I have heard of this problem causing the motherboard to keep rebooting. I would have never figured that one out (well, never maybe a tad harsh). I can only say that it's a good thing the light was blinking!
'The way IT should be!'