AvFan's right that making sure all cables are properly seated is an excellent place to start, but we may need to dig a bit deeper into how you have everything connected to resolve the issues you are experiencing. The symptoms you describe make me think first of HDCP handshake problems, assuming that your cable box is connected to the TV with an HDMI cable.

First, a few questions. What DVD player are you using? What model of DVR cable box do you have? How do you have the cable box and DVD player connected to the 990? How do you have the 990 connected to the TV? Do you have any video signals going directly from source component (cable box or DVD) to TV?

Second, a few thoughts. First, you'll want to have digital audio from both the DVD and cable box (optical or coaxial, doesn't really matter which). You'll want to make sure that both DVD and Video1 are configured to use the correct digital inputs. (You mentioned a hard reset - if that was on the 990, it would have wiped out all of your settings and you would have to make these settings again.) If you have HDMI going straight from the cable box to the TV but you don't want to use the TV's speakers, you may want to adjust the cable box's settings to disable audio over HDMI - which is the most likely reason you have been getting audio to the TV at times.