Please do try these troubleshooting steps that I've suggested to others who had the same problem.
- Do a hard reset first before starting, remove the battery and AC adapter then press and hold the power button for 20 seconds.
- Start by uninstalling/reinstalling the keyboard driver.
- Go to Device Manager and uninstall the keyboard driver then reboot your laptop. It will reinstall the driver automatically.
- Next is to make sure that Keyboard settings are all set to United States.
- If all these will not work try an external USB keyboard and see if the same problem will persist because if it will not happen you'll need to do a complete factory reset.
- How to perform Factory Reset: http/www.isunshare.com/blog/restore-gateway-laptop-to-factory-default-settings-without-cd/
- And if the factory reset will not work the only solution would be to replace the keyboard itself.