Same as what richc46 sugguested:
Power your laptop off completely.
Step 2
Take the battery out of the laptop. Typically the battery is located underneath the laptop towards the top.
Step 3
Leave the battery out for 30 seconds. This will allow the laptop to refresh itself.
Step 4
Put the battery back into the laptop.
Step 5
Power your computer on. Once your computer has rebooted, check to see if the keyboard is working.
Step 6
Open the "Start" menu on your laptop, if the keyboard is still locked up.
Step 7
Click on the Control Panel.
Step 8
Go into the "Accessibility" options.
Step 9
Open the tab labeled "Keyboard".
and also
laptop (HP) it's FN + F8 pressed at the same time