OK, I need some help installing my new Roamio. I bought the 4 tuner model. Here's what I did: 1. I moved the cable from the wall from the DTA installed by Comcast to the back of the Roamio. 2. Since I have never used HDMI, I don't have a cable. I do have an ethernet cable so I plugged that into the Roamio and also into the TV. 3. I plugged in the power on the Roamio. 4. I made sure the TV is on Channel 3. I expected guided setup to start but I've got nothing but static on the TV. What am I doing wrong? Does it have to be HDMI?