Computer code on top of screen on device stuck in Restore mode. How do I get it out?

i have an iPhone 4s that I am trying to repair. It has what looks like computer code visible on the top of the screen. What causes this and how can it be cleared?

Won't do anything and iTunes doesn't see it. The phone is for a friend who knows nothing about. He runs a pawn shop and it was brought in like this. Any help,would be greatly appreciated.