onkyo tx-nr609 only one HDMI input working

[edit- renamed from "onkyo tx-nr609 Cable won't show" - see second post for more details]

just installed my Onkyo tx-nr609 but Cable isn't coming through.

Hooked up through the Cable/Sat HDMI port but all I get is the blue screen and no audio, as if nothing is connected.

I've played with resolution settings on the receiver some but nothing has changed

Cable box: SA Explorer 4250HDC
TV: Dynex DX-LCD32-09, which has a 720p resolution.

Still playing with it. It seems to be an issue with the ports.

I unplugged the BD player (which was working) and connected the cable box to the #1 input and cable works now but the BD player won't play on any of the other HDMI inputs now.

Okay, resolved it by myself.

I bought it as an open item at Best Buy and as far as I can tell, while it spent time as a display model, Best Buy apparently reassigned all of the other HDMI inputs as "------", and being a newbie to setting up something like this, and thanks to the somewhat vague manual instructions (p.44), it took me awhile to figure out how to switch them back.

Now if someone had any suggestions about my other issue, I'd be a happy camper. That may be a problem with my computer or TV, but I'm a bit confused as to why no one has even been able to point me in the right direction on these two posts.