[I was completely off in my assessment of what the problem was. See my reply to klricks.]
Somehow I have messed up something in the boot process on my Pi. I always boot to command line, but for this project I need it to boot right into the desktop. I set that up through raspi-config. Everything was working fine until I plugged in a USB hub. I am not sure the USB hub had anything to do with the problem, but now it won't boot and that was the last thing I did.
The Pi seems to boot fine up until it tries to start the Desktop. Then it actually acts like it shuts down. The screen goes black and the green activity light seems to be doing something. After a few seconds the HDMI connected monitor loses connection with the Pi. The monitor's connection LED indicator starts to blink like there is nothing connected.
At this point I can't get the Pi to respond to any keyboard input and the green light is completely dead. It is just like the Pi is halted.
What I would like to do is edit the right file on the SD card from another Linux machine that will force it to boot without starting the Desktop/lightdm. Because the Pi won't boot up completely I cant run raspi-config again to set it there. Does anyone know what file and what line I'm looking for?
This particular setting doesn't seem to be in the /boot/config.txt file.
I've also tried booting into runlevel 1 and running raspi-config from there. But it doesn't seem to save the configuration. Because it acts exactly the same after running raspi-config and setting it to boot to command line.
I appreciate any pointers. I don't want to have to rebuild this SD card if I can keep from doing so. But too many more hours on this project and I might need to. I have to actually get back to doing real work at some point instead of fighting with this.