I had completed setting up my new Roku Express and it was downloading the channels when all of the sudden the screen on my TV went blank.
The TV was still on and the Roku was still on but it no longer displayed anything. I tried to change the input on my TV and the TV registered that I was clicking the input button but nothing would display on the TV.
It seems as though the LEDs on the TV screen are no longer working. Nothing was wrong before I tried to set up my new Roku, so I believe the events are related.
Sorry, there's absolutely no way the two events are related. If your screen lost its backlight, you might still be able to see some motion if you look closely at the screen. That would help identify if it's the backlight or the screen itself.
But regardless if you have LEDs or fluorescent bulbs as the backlight, there's simply no way a device connected to the HDMI port could cause it to fail.