I found the solution to this probelm on another thread- here's the link: http://forums.xfinity.com. We have older boxes and remotes on nice HD tvs but still enjoy watching some shows on SD channels not available in HD. The pictures on all SD channels suddenly appeared stretched as of a few months ago. I hate dealing with Comcast Service, so I was relieved to find the answer, and it worked like a charm! PS- had no idea you could access settings with the box turned off- genius!!
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