i wanted to thank muldermj for posting this resolution.
my cable box and apple tv registered "no signal" (slots 2 & 3 respectively)
Yet when i swapped the other HDMI cables into HDMI4 they worked fine. i had called my cable company and everything was fine on their end.
i followed the instructions by muldermj except i waited 10 minutes and this did the trick.
i unplugged all my hdmi cables, powered down my surge protector, waited 10 minutes, powered the surge protector back up, plugged all cables back in and voila!
hope this helps anyone else with similar problems.