Try this and see if it fixes it.
1. Uninstall the keyboard driver.
2. Reboot the computer. (Yes, without installing the driver just yet.)
3. When the computer starts back up, it should reinstall the driver on its own.
If that doesn't fix it, I would start looking at issue with the keyboard itself. To test that, try turning off the laptop, connecting an external keyboard and then turn it back on. If the external one works fine, then you need to look at the attached one.