Wecome to the forum.
1. If the TV worked fine before the cable/sat box, it could be the box interfering with the unit. We are aware of only one series that had an IR issue, which is the A850 series. However, there are also several instances where cable boxes can also emit IR, and maybe taping a piece of paper over the IR sensor might help. It's a terrible suggestion, but can be a workaround.
2. I'm not sure about how broadcasting in Canada works. But what I can say is that with an HDMI cable, the digital signal is reproduced on the screen as it is transmitted. An analog signal would likely allow you to stretch or zoom in on the image, however, HDMI transfers the picture in a pixel-by-pixel format, so adjusting the screen isn't an option. Those options, however, would be available if you used an analog (composite, component, S-video, etc) input.
While that may not be a solution, I hope it helps explain why it works that way.
I have a couple questions regarding this TV. It had worked great until I signed up for a new HDTV service through MTS in Manitoba, Canada. MTS is an IPTV that uses a Motorola set top box (not sure the model, but I believe it is the same as what AT&T uses for their IPTV).
Problem 1 - Remote control. When I try to change channels with the Motorola remote, I have a lot of trouble inputting numbers, having to hit buttons twice, slow response time etc. I have read that this may have to do with the Samsung interfering with the remote. Can anyone confirm this, and whether there is a fix?
Problem 2 - I have my TV set up with an HDMI cable, and with the Motorola set to 1080i. The high def stations look great, but when I go to the SD stations, I am unable to stretch them to fill up the screen. When I try to change my picture size on the Samsung, the Zoom 1 and 2 options are 'greyed out', meaning I cannot select them. The 16x9 setting still shows up as 4x3 on screen. This is quite aggrivating.
Any help would be greatly appreciated.