I have two different issues with my PSP-2000 screen.
The first problem is that the screen has vertical lines from top to bottom on the left hand side. See pic below:
The other thing is that the screen has some sort of "water marks" for lack of a better term. I have never cleaned the PSP with any liquids, nor spilled any on it or dropped it in any. The weird thing is, is that my laptop screen has the same problem! Very weird!
It was very hard to get a picture of! These mainly show up on light-colored screens.