IsCGA()

         Detects if a CGA card exists

    Syntax:

         IsCGA() -> lCGA

    Description:

         Detects if a CGA card exists in the system and it returns a
         logic indicating the result.

    Return:

         .T. if it exists and .F. if not.

    Example:

         If IsCGA()
           ? "There's a CGA card"
         EndIf