The problem might be caused due to the gamepad. I myself have a Xbox One controller set up aside from my keyboard and when I switch from one another, there are some side effects e.g., When I play GTA V (with my controller) and I switch to PUBG. PUBG shows the controller keys instead of the keyboard keys. My theory is that your Gamepad blocks the input of your keyboard. My solution to this was to manually disable the controller when I am done with it (I know, a bit tricky). SOLUTION: Go to Control Panel--> Devices and Sounds--> Devices and Printers. You should see your Gamepad between those devices. Right click on it and delete the device. Whenever you feel the need to play with your Gamepad again, just repplug the gamepad back into the USB-Port.