I just got a HD Cable Box from Comcast, a Motorola DCH3200 and I have it hooked up as component. I switched it over to HDMI (The same cable that I use for my DVD player to see if it was better) and when I turn the box on Video and Audio come up on the screen and after 3 seconds the video disappears. I can still hear the audio. Component works fine.

Solved!

I'm having a similar problem. Can you post what your solution was. Thanks in advance!