its not dead its stuck
if it was dead it would be black and harcly noticable
I believe the warranty only covers it if there are a specific ammount of dead pixels
but the good news is that stuck pixels are easy to get rid of usually
the easiest way is massaging it with a soft cloth
if that dosent worktry applying slight pressure to it and turning the device off and on repeatadley
after that there are software options but i am not aware if there are any for the psp