Might be a PC/Laptop issue, try restarting your device, make sure nothing is stuck in the keys, unplug the keyboard if you're on PC. On laptop you may have to shut it down and hope. If there is another computer in the house, try to login using the other one, see if that's the problem, and gradually figure out what the problem is.
I probably didn't help at all, but I tried. At least to my knowledge.