It seems like it may not be booting from the microSD card.
Can you check whether the card is plugged in correctly - perhaps remove and re-insert the card. You should see some green flashes from the activity LED when it starts to boot from the card.
To eliminate some possibilities - it may be helpful to start off with an external display connected via HDMI and a keyboard and mouse connected via USB for initial set-up, adding the screen only after you complete initial set-up and updates.
Failing that, you may need to re-image your NOOBS card with the latest image from the official Raspberry Pi Foundation website as it could have somehow become corrupted or may have an out-of-date version that doesn't support your particular model of Raspberry Pi.
Thanks for the suggestions. So far I have tried reinserting the card with no changes in any LEDs. I've connected a 3 amp power supply to the positive and neg. pins and have the same red LED on. I have also connected an external display that shows a no connection signal using the HDMI cable. I've changed the HDMI cable. I believe I've changed everything except the Pi. and perhaps the card.
In the words of a childhood friend,Uggh!
You might try to remove everything from the Pi and try to boot it without the display to HDMI. If it is still not booting, then you should burn the latest Raspberry Pi image to an uSD card and then when it boots run the following before adding the Display.
sudo apt update sudo apt upgrade
If you have a volt meter, you should check that the Pi is creating 3.3v and 5v on the appropriate pins when powered on. If not, there the Pi may have been damaged.
This link has some of the common solutions to a non booting Pi.
Did you try to power the display separately?
Hello and thanks for checking this out. I am totally to the world of Raspberry but I am thinking that I might have a dead board or I'm completely lost. I've connected the 7" element 14 touchscreen and a Pi 3b together and inserted a NOOBS card. As I understand things I should get some response when I power it up with a 5v 2amp supply. So far, no joy, just a black screen. The only LED turned on is one red LED near the power jack. I hope you might have a simple clue. Thanks