Please forgive all caps, as I am not yelling, but simply stating a fact that people don't understand.
HDMI IS NOT A STANDARD!
"What does that mean, to me, the layman", you ask.
It means that not all HDMI devices HAVE to PLAY well with each other. Standard and PROTOCOLS (TCP/IP is a protocol for networking, or PCI Express [Peripheral Component Interconnect Express], is a computer bus standard https://en.wikipedia.org/wiki/PCI_Express).
HDMI is not a standard.
Always verify the input is on correct input (looks like you covered that).
The best thing to do, is fiddle with the booting order of stuff. So, what that means, is boot the pc first then change the input on the TV, or vice versa!