I apologise if I have mislead you about my problem. As I said in my original post, I don't know if I have a problem with my computer, my software or my device. All I know is that nothing I have tried has solved it. I have been able to get my bluetooth device paired with my computer but when I try to upload the sketch I get an error message. It happens regardless of which port I choose. I am assuming (perhaps mistakenly) that because my device is now paired with the computer that the problem lies elsewhere. Here is the text of the error message generated by Arduino:
Archiving built core (caching) in: C:\Users\Ross\AppData\Local\Temp\arduino_cache_733992\core\core_arduino_avr_uno_0c812875ac70eb4a9b385d8fb077f54c.a
Sketch uses 2932 bytes (9%) of program storage space. Maximum is 32256 bytes.
Global variables use 260 bytes (12%) of dynamic memory, leaving 1788 bytes for local variables. Maximum is 2048 bytes.
C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avrdude -CC:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf -v -patmega328p -carduino -PCOM5 -b115200 -D -Uflash:w:C:\Users\Ross\AppData\Local\Temp\arduino_build_315079/RC_lightseeking_sensors.ino.hex:i
avrdude: Version 6.3, compiled on Jan 17 2017 at 12:00:53
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
Error opening serial port 'COM5'. (Port busy)
Invalid library found in C:\Program Files (x86)\Arduino\libraries\Smart-Robot-Car-Arduino-master: C:\Program Files (x86)\Arduino\libraries\Smart-Robot-Car-Arduino-master
Invalid library found in C:\Users\Ross\Documents\Arduino\libraries\Circuit_0101: C:\Users\Ross\Documents\Arduino\libraries\Circuit_0101
Is there anything there that provides a clue as to why I can't upload the sketch?