I can see the point Robin2 made: well the program was not big, either complex. For test purposes I loaded 100 steps back and fort program. At this given moment I have only win10 and cannot test other os systems, unfortunately.
OldSteve - Now I have uploaded program from Examples-Basic-Blink. This is three lines code. And when I type $ or ? in the serial monitor, there is no action. So, seems I am not having any communication from the Arduino back to the pc, but I can load whatever I want and the Uno will run it.
How do you see the problem?
What CrossRoads said.
When I said this "Write a very simple sketch to test communications. If you still have problems, post that simple sketch here."
I meant a simple sketch that includes serial communications.
Blink has no serial communications, so how can you expect to receive any serial input into the serial monitor?
Before typing ? or $ and expecting a response from an Arduino sketch, you must first write code in the sketch to receive the serial input then act when a $ or ? is received.
Did you not know this?