Hello and good job.
I installed ARDUINO 1.8.12 on a 64 bit Win10 PC.
I connected my Arduino one and identified the port as COM5.
In the programming tool I correctly made the settings relating to the type of card and port to which it is connected.
I tried to execute the BLINK sketch but I get the following error message:
avrdude: Version 6.3-20190619
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch
System wide configuration file is "C: \ Program Files (x86) \ Arduino \ hardware \ tools \ avr / etc / avrdude.conf"
Using Port: COM5
Using Programmer: arduino
Overriding Baud Rate: 115200
avrdude: ser_open (): can't open device "\. \ COM5": Access denied.
I did the same tests on another Win10 64bit PC and on a Win7 PC.
Everything is working here.
I also tried to run some tests with the B4R Tool on the PC with problems. I get the same problem accessing the COM5 port.
Thank you for your kind collaboration.
I could have some help to understand what happens.