Also maybe the refresh rate. Connecting to the TV is like hooking up your comptuer to a 800x600 monitor. I believe thats the highest resolution most TVs support (i have no idea about the newest TV models, and their resolutions). So yea, hook up your system to a regular monitor, and make sure the screen resolution is 800x600 and check your refresh rate and choose something low (60 Hz or so). Then shut down, hook up to TV, and boot
Good luck