Not everything on the stations that you listed are broadcast in hd. When that happens you will get the borders usually on the sides, somtimes all around like a photo mounted on a black background. It's not your tv it's the networks.
ive had hdtv for about 2 weeks now - comcast-digital-hd - looks great - a few days ago some hdtv channels were no longer in widescreen format - espn,abc,nbc,cbs,fox have a border on the sides - other hdtv channels looks ok - my tv is panasonic lcd. is this the signal, tv or what?

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