I have had this problem for about 2 months now but I have had my xbox elite for around 2 years. Not sure why it started but when I cut my system on the video and audio does not immediately show up. I am running it through a reciever to a projector via HDMI. It worked for the last 2 years perfectly and just recently stopped. The only way I can make it work is to cut all the systems on and press A on the controller to start the game (the xbox powers on and works fine and I press A to start the Game, no audio or video I can just hear the xbox processing as is starts the game) then I switch the inputs to my cable and cut the cable box on. Cable works instantly as does my Wii and Bluray player and they are all hooked up thru the same reciever (2 of the 3 are hooked up via HDMI). So I switch the input ot cable and watch tv for about 5 mins then I can switch the input back and the xbox video and sound come on and im at the start screen in whatever game I put in.
I have unhooked all cables and rechecked everything. It is obviously hooked up just fine since it works after being on and changing inputs after 5 mins. I am pretty tech savy and my friends and I cannot fix it.
Thanks for any help.