Joprp05:
So, let me throw in some backstory. I changed my computer for a new one and was checking all my sketches, just some routine check. Then, I went to test my 'calculator' I made a few months ago.
Are you saying that this program worked when you were using the old PC and WITHOUT A SINGLE CHANGE to the Arduino program it is not working now?
If so, are you now using a different version of the Arduino IDE? And if so have you tried installing and using the version of the IDE that you used to be using? (You can install sever versions of the IDE on a PC).
To be honest, I can't see how the version of the IDE could cause the problem, but it would be interesting to try.
...R