windows 7 - Keyboard input is not working in Firefox ALONE

This has never happened before. I went through the following steps in trying to solve the problem:

• I was initially using Firefox beta. I updated it but that did not solve the problem.


• Uninstalled Firefox beta and installed the mainline version and made sure to check for both Firefox and Windows updates. Problem still persisted.


• 
  

  Restarted Firefox with all add-ons disabled. Problem still persisted.

  
  


• 
  

  Restarted Firefox in safe mode. Problem still persisted.

  
  

I'm frustrated and stranded. I'm running on Windows 7 Professional 64-bit.

Answer

Uninstalling, rebooting and reinstalling solved the issue. Still don't know why it happened though.