So, it turns out that the HDMI imput #1 on my LG TV is not working, whereas the other imputs are working. And the cable box IS working. So I kept everything like it was before, only I ran the HDMI cable from the AVR into imput #2, and still no video signal. So I performed the HDMI reset you suggested again, and it still does not work.
I'm at a loss here because I would like to avoid resetting the microprocessor if possible.
Another odd thing is now when I use my LG tv remote to power off the TV, it also turns off the AVR, which did not happen before. I have read about the "HDMI control" function in the owner's manual. Could that be the issue? The manual does not state how to turn this feature on and off.