Instructions
Connect your Xbox 360 Elite system to the Internet using a Live account. This will allow your system to automatically check for Dashboard updates. Once any updates are installed, see whether this has fixed your problem.
Adjust the HDMI display settings on your Xbox 360 Elite through the Dashboard. Set the setting to optimal resolution first and test your display. Run through each of the three optional resolutions.
Connect the HDMI cable from the Xbox 360 Elite edition directly to your television HDMI port. If you have any devices plugged in (such as a home theater system), remove the plug from that device and plug it directly into your TV instead.
Ensure the HDMI cable is plugged into an HDMI port and not a DVI port. DVI ports do not support all the same features that a HDMI port would and could cause display problems. If your TV does not have an HDMI port, consider plugging in your Xbox 360 Elite system by another method.
Turn off any image-enhancement or digital noise-reduction features for your television. Sometimes these features can cause interference with your Xbox 360 Elite gaming system.
Connect your TV to your Xbox 360 Elite system using a method other than HDMI. The component HD, AV cable or VGA AV cable are all alternatives to the HDMI cable and may stop the flicker.