Can not connect my Xbox to my TV

Hi there Nicky! Christopher here, an Xbox fan and been on Xbox for years already. I would really love to make your day by helping you out. Can you better describe the Xbox/T.V situation, please?

1080i does not work at all. And to add to my problems even more 720p no longer works now I can only get video or audio using 480p. I dont think it is my TV because I tried to connect my XBOX to another TV and got nothing, and I can connect my computer to
my TV with no problems. Any help is appreciated.

I have had the a sort-of same issue. I had my Xbox Connected to my TV and resolution 1080p, then i went to my friends house and hooked the Xbox to his TV and no Video came to the TV... As my friends TV didn't support 1080p, needed to connect it to a TV
that supported 1080p and then i changed the Resolution to the lowest, and the connected back to the friends tv and then it worked.

If you had a power outage, I get a few, you may have to turn TV on with switch, not with remote and check SOURCE.

Ship it in for a repair. Probably the only thing that will work.