Home, menu, back and search keys were working perfectly fine, moments ago. After hitting the back keep to exit an app I noticed that it didn't respond , so i tried the other keys and the same result. Can anyone provide an explanation as to why this happened or any solutions to remedy the problem. I've done a soft technical troubleshoot of the problem: Restart - problem still exists Turn off phone, remove battery, install battery, turn on phone - problem still exists. The feedback will be greatly appreciated, thank you.