Please do try these troubleshooting steps that may help.
- First is to uninstall/reinstall the keyboard driver.
- Go to Device Manager and uninstall the keyboard driver.
- Reboot the laptop once the keyboard driver has been uninstalled and test it again after the reboot.
- If the same problem will persist I would should suggest opening the laptop and check the ribbon cable that connects the keyboard to the motherboard.
- If the same problem will still persist the problem then lie in the keyboard itself.