Win10 install killed video output

I was upgrading a perfectly functional, 5 year old, Win7 desktop to Win10 using the media creation tool on a USB drive. When I had tried on-line upgrading this machine got hung up on "checking for updates" which is why I went to the MCT and disabled updates up front. After the "Installing Windows 10" message came up, I left the room. When I returned about an hour later the monitor was blank with the message "no input". The only sign of activity was the fairly regular blinking of the LED for the SSD where Windows is installed. I let it run for 8 hrs. like this. Then I hit reset...still no video so no visible POST and the SSD LED returned to blinking. Then I did a hard power down...same thing. I haven't built another computer since this one in 2011, where do I start?

If you're not getting a POST display, you have problems beyond the OS.

All that I can suggest that doesn't involve real hardware troubleshooting is clearing the CMOS.