Background
Of late, I have been encountering an issue with my Windows 7 based laptop keyboard. The keyboard does not work intermittently at the Windows login screen and afterwards. This is very frustrating and a Google search revealed that there are many people who are facing the same issue which has something to do with updated USB port drivers. Since I was unable to fix the issue using any of the proposed solutions, I have come up with a solution which is easy and is working for me from the past few months. I hope that it helps you too.My PC configuration : Lenovo Z580, Windows 7
Issue : Integrated keyboard and external wireless keyboard do not work in Windows but work in other operating systems like Linux
Solution
Windows Login screen
Here, one needs to enable login either without a typed password so that you can just click your username to login or use an alternative authentication method. I use Lenovo VeriFace to login on the basis of facial recognition.Windows Desktop
Launch the "On-Screen Keyboard" utility bundled with Windows. Go to START menu-> All Programs -> Accessories -> Ease of Access to find it. If Ctrl or Shift keys are highlighted in white, then just press the corresponding keys to remove the highlighting. Press some random keys and then CLOSE the on-screen keyboard. Now your keyboard should be fully functional.You need to repeat the above steps whenever you login to Windows.