Video configuration/calibration

Hello. My name is Rick.

I have been trying to recalibrate my settings or use the calibration by going to settings on my Mac but it seems I am only able to use 50% of the square when it shows a perfect square plus it won’t let me go to the bottom right of the screen. It’s like it’s overly big – the screen is too large to fit on the computer. I don’t know how/why this happened but when I clicked on the radio, this started happening. I don’t know what to do as this has been happening and it won’t let me find the perfect square nor minimize the video so that it can fit in the computer screen.

What can I do?

Rick