Lumia 920 Screen does not respond with keys blink for few seconds

[Money Sharma]

I am having Nokia lumia 920. Sometimes my phone's screen does not work. I pressed the unlock key but it does not makes any difference. Keys blink for few seconds and goes off again. Then when i tried to call it from another cell it worked and display worked fine. It has happened two times in previous three days. It is worrying me please suggest me. I have Black software update in my phone but the problem is similar to this http://answers.microsoft.com/en-us/...0/3661649a-0209-476d-aaf8-56987e30b157?page=2. Also my phone's info is here in the image.