Procedure Init(Installed:Boolean)

    If this procedure is  passed  False,  the  unit  will assume there is
    no mouse.  If it  is  passed  True  a  check  is  made for the mouse.
    If no mouse is found, Active  is  set  to  False, otherwise it is set
    to True.

    This must be called after  you  have  selected  your  video mode with
    TextMode.