Lester
I am puzzled by your statement that you cannot get any of the compiler options to work. There is usually no immediately visible impact when using these options. You can see if an option is being used by the compiler by reading the .LIS file produced when using the /EXPLIST option.
There is an menu item on the 'View' menu to view the Project Explorer window. If it does not work then it probably means that the window is undocked and is somewhere off screen. To get it back again you can try setting your screen resolution to it maximum value or reset the Plato window position settings.
Let me know how you get on. I cannot remember if the window positions are in Plato3.ini or in the project.ini or in the registry.