I have a Zenith d52wlcd and the screen is dark or excessively blue.

Go to the Zenith repair site. This has been resolved in a lawsuit. Zenith will fix it free of charge through 7/1/2010. The shop just picked my up to replace the light engine free of charge. Call 1-800-228-1757, have your model number and serial number, and where you purchased it. Here's the neat thing-the question I asked is "have they fixed the problem with the light engine, or is it going to keep going bad?" If happens again (blue lines/spots) before 7/1/2010, they'll replace the TV with a new and different TV of equal value!