Despite searching I haven't been able to find an answer (also have a call in to Comcast Tech).  I'm in Houston, TX using Comcast as the provider (digital cable), just started the service-using Scientific Atlanta Explorer 4250HDC, I have a Sony LCD-HD connected via an HDMI cable directly to the cable box-works great.  However, whenever I connect my (S-video/audio in) MCE2005 system to the S-Video/Audio out on the cable box, I get a "Copy Protection" error on the TV (which is also used as the MCE monitor) and on Media Center, so I can't record anything if the TV HDMI cable is plugged in.  Error goes away if I unplug the HDMI cable and just watch via the VGA out from the MCE system.

Thanks!

What kind of video card are you using? Maybe it's not compliant with the latest HD-drm standard (whatever it's called). If updating drivers doesn't work, you might have to get a new video card. Has it worked in the past? I had that same cable box for a couple years.

That's a good point-it's a Hauppauge WinTV-PVR 250MCE (it's probably at least 3 years old).  I'll give the driver update a try and see what happens.  May end up needing a new TV Tuner card (I'm assuming that's what you're referring to as opposed to the video card, which is a GeForce 6600)

And unfortunately, no, it's never worked-this is a new cable setup.  I've had the MCE computer for a while, but the apartment complex I'm in just switched over to Comcast.

I was talking about the Geforce video card. I don't know if the older 6600 has the latest copy protection deal.