ADJUSTING YOUR SCREEN RESOLUTION

First - do you need to change your screen resolution?

To check this, make sure that the window you are currently using is set to "full screen". If the symbol just to the left of the at the extreme top right of the window looks like , then it is set to full screen, if it looks like , then click on it to change it.

Second - see if you can see a box that says "OK". If you can see this, then your screen setting should be fine.

If not, I would get some expert assistance to change the screen setting.  While it is usually quite easy, every version of every operating system has a different method of changing it - so I can't explain it here.