Buttons like OK, Cancel, and Help are not visible at the bottom of the dialog. This can happen because of the vertical resolution, which does not allow you to show the whole dialog in one piece.
Use shortcuts to move the dialog and show the buttons on the visible part of the screen.
1. Press ALT + Space.
2. Press M or select Move.
3. Use arrow keys to move the dialog on the visible part of the screen.
4. When you are satisfied with the position, press Enter.