Hi,
Please do try these troubleshooting steps that may help in solving the issue.
- Start by doing a hard reboot, remove the battery and unplug the AC adapter then press and hold the power button for 20 seconds then try it again.
- If this will not work, connect an external USB keyboard and see if that will work or not.
- If the external keyboard will work uninstall/reinstall the Keyboard driver from Device Manager.
- If these will not work either last option would be to reinstall Windows.
- Again if reinstalling Windows will not work then it's a hardware problem already.