Ok, if it says it's up to 720p then your max resolution is going to be around 1280 X 720. That's probably just fine since your graphics card is fairly weak. You might also be able to use 1366 X 768. Windows should be able to detect the correct graphics mode as soon as you plug in the HDMI cable.
Yes, what is the native resolution of the TV and what Graphics card do you have? If you can run it at least at 1080p(1920X1080), that would be good. Most newer TV's do support 1080p.
You stil didn't identify the native resolution of the TV. Can you post a link to the manufacturer and model of the TV? However, the Radeon HD 5450 should have no problem displaying on the TV although gaming performance may be a little slow especially at 1080p even on those games.
Ok, if it says it's up to 720p then your max resolution is going to be around 1280 X 720. That's probably just fine since your graphics card is fairly weak. You might also be able to use 1366 X 768. Windows should be able to detect the correct graphics mode as soon as you plug in the HDMI cable.