my phone started doing this last week. calls came in and I could not answer them because the phone has no alternate way of answering a call. I had to literally take the battery out to restart the phone and it's gets frustrating when it happens when an important call comes in. other times I can be dialing a number or typing a text when the screen goes dark after 2 seconds...I push one of the keys to light the screen and lose all I was doing then the screen goes black again!!!!!