If the SpellCheck 
icon is not visible, it means that either no dictionaries have been downloaded or none have been selected. You can check this by going to the Menu, clicking on Tools -> Options and on the first tabsheet, click on the 'Configure' button to the right of 'Dictionary'.
If there are no entries below the 'Dictionaries' heading, you can find information about downloading dictionaries here.
If there are entries, click in the box in the Name column to select the dictionary/ies you want.
Once a dictionary has been selected, the SpellCheck and LiveSpell icons will be visible.