Sometimes my Dell W3000 30" HDTV does not illuminate when my computer is turned on although the green power LED is illuminated. It is in stand-by (LED is yellow) when the computer is shut down. To correct the problem I have to toggle the power button off and on to get the TV to display my desktop.
I have the same problem. I am collecting reports of the same and sending them in to the State of California Department of Consumer Affairs. You can help out by forwarding the nature of the problem with your Dell W3000 LCD TV to my email address. I can keep you updated if you like.