If it’s the .blend file just resize your blender window. If it’s a runtime (.exe), press F10 and on the right most panel you’ll see Game Frame Settings. Adjust it to the pixel size that’s full screen, however, not everyone can run the same resolution size so beware.
Open up blender, press F1, find the .exe and open it up. However, some of them are autostart (still not sure how to look into those).
For the second question, I need to know how to have a game or .exe file adjust itself to the full screen resolution of any viewers display automatically, no matter what the display is set at.
The third question is for opening and seeing the construction of a .blend that has an autostart.
After running some test I see that by setting the runtime options to fullscreen, the file will adjust to the display size no matter what the display settings are.
This is my answer to the second question.
I now only need an answer to my third question at top.