Reply for Silly HDMI problem.
this from MR.NK "I'm using a Sony-TV too and the picture was 1080p and of a normal quality. Did you use the mirror-setup? You have to go for extended or only second-screen setup, so the surface can change the resolution for your TV up to 1080p."
when using mirror monitors the 2nd monitor will be locked to the same resollution of the pad.
If your TV is true 720p it won't be able to open Modern UI Apps due to the 720 refers to 720 Horizontal Pixels and you need a minimum of 768 Horizontal Pixels to support the UI. Some 720p are actually 1366x768 some other support 1024x768, but if you're stuck at 1280x720 it won't work...