Originally Posted by morydees
Sheesh, LCD burn-in. It's physically impossible. There's nothing to "burn" in. The light is behind the display--hence the term "backlit"--and the LCD simply filters the light into an image. Image persistence occurs when a liquid crystal is left in the same configuration for a prolonged period of time, but it is absolutely NOT the same thing as burn in and is usually temporary.
Burn in is just that: An image being literally burned into the phosphors of a CRT or plasma display. It is a permanent condition. You can turn the display off and still see the burned in image, because it is indeed burned into the glass.
Anyway, now that that's straightened out, the reason that the units that were sent in for repairs were returned without any work being done on them is because while they were in transit, they were presumably turned off, allowing the liquid crystals to relax, thereby alleviating the image persistence issue. Leaving it off for an extended amount of time was what fixed it, not the fact that it was sent to HP. You could have shipped it to your grandma and back and it would have been just as fixed.
Or you could just leave it off for the same amount of time.