I started experiencing this today. I started with 1 white vertical line going all the way through the screen. I thought it was no big deal so I restarted and it didn't go away. 30mins later I have another white line. Right now I have 18ish WHITE LINES across my screen no matter what program is running or screen it is on: Internet Explorer, Home Screen, Programs Menu, Settings Menu. I restarted my phone and the lines even show up on the HTC Startup menu
