Did you try my suggestion? We are still here to try to resolve your issue but it's difficult without feedback.
OK, so if I understand, your TV is HD ready but not 1080i/p capable. The two features are different. The primary issue, as I recall, is that your DVD player will not play full screen. Is that still an issue? Can you tell us the make and model of your TV? From that I can tell you what should work and what WILL not.
This TV can accept a 1080i signal. http://www.sony.co.uk/product/t15-l-series/kdl-19l4000/tab/technicalspecs If you continue to use your upscaling DVD player you must manually set it to 720p or 1080i per my instructions above. 1080p will not work. If you are watching an SD TV signal on an HDTV you will always have black bars on the side unless you set to wide kmode but you will either chop off the top and bottom or streatch the picture. Best of luck.