Meg93931:
Oh, thanks for explaining. I think that I wanted the Arduino to do something that is not possible.
Oh, right. If you saved a variable or variables in EEPROM, with status info, you could then read that info in 'setup()' and act on it, possibly. EEPROM storage is 'non-volatile', so does not disappear when power is cut.
I will just press the reset button from now on. Thanks
Regarding the fact that there's no printing to the display on power-up until you press RST, upload or open the serial monitor, that indicates that you might need a short delay in 'setup()', to give the display time to initialise before you start sending print commands. Edit: You could try about 500mS, then if that works, keep reducing the delay and testing until you find the minimum delay that's required, then just increase it by a comfortable margin to ensure reliable operation. It definitely should be possible to get the Arduino to print to the display on power-up without having to press RST.
Is this an OLED display, or another type of LED display with an on-board controller?