HDMI as an interface sucks.
You may want to try another cable or make sure that your sending a video signal over the DVI port.
Do you have an external monitor that you can hook a DVI cable into?
The unfortunate reality, is some TV's have issues with the type of cable plugged in to them. I've heard of some folks having issues with those $150 monster cable HDMI cables to various TV's, while a $20 cable works just fine.
You might also want to check your TV setup. The resolution that your trying to sync up to the TV with may "not be supported", meaning that you may be sending an oddball resolution and the HDMI settings won't sync up. Check the manual and see if the resolution you have the video card configured for is supported by the HDMI connection on the TV. You may need to change the resolution on the video card to allow the TV to connect.
I know that some TV's have "dot by dot" mode (not sure of the exact terminology) which is usually a configuration on the TV in the menu options. It's an option specifically for computers to avoid additional processing by the TV's internal processor. I believe it turns off overscan? I don't know your TV, so I can't help you there.
Good Luck,
Mike...