Two other possibilities:
Receiver is set to a resolution the TV can't handle. Use the res button on the front panel to go through all the resolutions to see if you can find one that works.
HDMI output from the Genie, or the cable, is faulty. Check the Genie with another HDMI cable into a different port on the TV. Try using component cables (red/green/blue, plus red/white audio) to the TV to see if that works. HDMI interfaces are notoriously prone to damage from lightning (grounding issues usually)
