Try following steps first and check after each step
- Run Keyboard Troubleshooter
Type Troubleshoot in Windows Start Search box > Click Troubleshoot > Scroll down and click Keyboard > Run the troubleshooter > Follow onscreen directions
- Run Hardware & Devices Troubleshooter
Type Troubleshoot in Windows Start Search box > Click Troubleshoot > Scroll down & Click Hardware & Devices > Click Run the Troubleshooter & follow on-screen directions > Restart the computer after troubleshooting is completed
- Uninstall Keyboard Driver
Windows Key+X (Or right click on Start) > Click Device Manager > Expand Keyboards > Right click on Standard PS/2 Keyboard > Click Uninstall > Reboot your computer