Try shutting it down and then attach an external keyboard. Then turn it on. If it will let you log in then, your attached keyboard may be the issue. If it still won't work, then you can try starting up the laptop in "Safe Mode" and see if it will work. If it does, then there is something on the device that may be hindering it from working correctly. You would have to remove whatever it is to get it working again.
How to enter "Safe Mode" when booting the computer.
In Windows 8 and 10...
As your computer restarts, press F8 (possibly a few times) to enter "Safe Mode"
a. Press the "F4" key to Enable "Safe Mode".
(The computer will then start in "Safe Mode" with a minimal set of drivers and services.)
b. Press the "F5" key to Enable...