I purchased a 24" iMac back in 2009, and though I've been happy with its performance thus far, I've noticed that perhaps the display has gotten "dirtier" with a yellow tint over time. I'm not sure if my eyes are just playing tricks on me, but I could swear that the brightest whites just aren't what they used to be. Is there any way with a diagnostic test that I could confirm it? And what are my current options for treating it if the display has indeed gone awry over time? Will Apple honor my purchase with some kind of consolation service or will I have to bite the bullet and foot the bill?