If none of this works try your key commands, if your player isn't responding may be your keyboard and/or your mouse has incorrect or no commands set to them. Usually you will have one set of commands set for your menu and then change them when you load your level therefore having possible infinant amounts of commands for one key if in different states.
In your 3DGS manual if you search under "key mapping" you can find a topic named 'Keyboard' that tells you the key names (for a reference in your code) and there currect default functions.

You usually usually re-assign commands similar to this.
Code:
on_x = exit(); // press [x] to exit the game (exit() is a predefined function