This all of a sudden started to happen? Did you make any other HW changes? Have you scanned for malware?
You may need to disconnect any extra devices (especially USB) and uninstall the driver, reboot and see if Windows reinstalls it. If the keyboard is failing, and you are handy with your hands, you can replace a notebook keyboard without too much hassle or expense.
Alternatively, you should be able to simply connect an external USB keyboard and use that.