Whats the deal then Eddie, did the new cable not help? Are you not using the new cable that has the red, green and blue connectors?
Check this out - Click
Mainly the bottome that says - A Note about DVI and HDMI. There are links in here for cables that it seems to think you need.
I cant help more than this as I dont have a 360 or a HD TV however, if you still have problems I will let you have my address and you can send them to me for testing. I can let you have the 360 back around November when the PS3 comes out but the HD TV might get lost in the post :ph34r: