The Problem usually starts with plugging in an external keyboard like an usb keyboard or wireless keyboard. The external keyboard enables the num lock and leaves the light on after you have unplugged the keyboard from you laptop.
To resolve issue on laptop disable the numlock, if cannot see the numlock on your laptop, Press the FN and the F10 Key Together (FN is located next to CTRL key on toshiba laptops. and the F10 key is on the first layer of keys of your keyboard ) to toggle off, the light goes off. Problem is solved. Hope this solves your issue.