Just recently my phone's screen stopped displaying correctly. I was using it and the screen all of a sudden went black. It was still on though and I could only see the screen once the brightness was turned all the way up. I tried a hard reset and that didn't do anything. Any suggestions on what I can do to fix it myself before going somewhere to get it fixed? It's still under warranty to. The screen looks like it has a bunch of tiny gray horizontal lines going across it.