need video knowledge ASAP

[sudbury78]

I have recently setup my surround sound and was using a 1080I set until I purchased a new TV and while I wait for delivery on my sammy 5271 I hooked up my bedroom TV to my receiver via HDMI and wanted to make sure everything work. Well, I have my ps3, hd-dvd and x360 hooked up to receiver via hdmi and then hdmi out to the TV. All worked great last night.

I plugged in my bedroom TV and all works great...except my cable/sattelite. I get a black picture with my cable box connected rgb on the receiver. When I click on the cable button on receiver, I get a blank picture but can see the actual channel changing on the guide. Does that make sense?

BUT, I can click on my recorded programs that are recorded via my DVR and sure enougfh I get video and Sound. What on earth? How is this possible? Does that make any sense?

I'm desperate for assistance as my New tv will be hooked up Monday.

Thanks