PSP Blue line problem?!

So my friend gave me his old PSP and the screen is in perfect condition (no scratches, dead pixels etc) but there is a problem that I've noticed. Alot of the time, I get these vertical light blue lines show up in the background. They are tiny but there are alot and seem like in a pattern, and are annoying (to me anyways). Anybody know what this is and how I can fix it?

hmm im not sure about this one i remember seeing some program which fixes dead pixel problems not sure if that would work though

but i think u would need the psp moded for it to work

there's also a thing called chilly willys key cleaner but i dont know if that would help

just hope someone with more knowledge comes around to help.