Hello, and welcome to Anandtech!
Please don't be upset if I'm going to point out that some of the stuff you wrote is hard to understand.
First of all, is this the TV you're talking about?
http://www.amazon.com/Sceptre-X320BV.../dp/B004J66GSQ
The description says it's a 720p TV - which is usually interpreted as 1366x768. However, some manufacturers use a slightly lower resolution of 1280x720. That may very well be a problem - can your computer be set up for that resolution instead?
Do you have any other monitor you can connect to your computer? If yes, please see if that one will work. Also keep in mind some TVs are unable to display anything on the screen between the time you power your computer and the moment you go into Windows, because of the lower/non-standard resolution of the BIOS screen.
You should try the VGA port as well... see if this analog signal is properly displayed.
Also, I have a few questions:
Does your computer have a VGA/DVI port on the motherboard? And do you also have a separate video card? Are you sure you're not connecting the TV/monitor to the wrong port?