procedure TForm1.BuildMenuTree(Path: String; Root: TMenuItem);
var
   S: TSearchRec;
   Rslt: Integer;
   Item: TMenuItem;
begin
 if Path[Length(Path)] <> '\' then Path := Path + '\';
 Rslt := FindFirst(Path + '*.*', faDirectory, S);
 while Rslt = 0 do
   begin
   if ((S.Attr and faDirectory) <> 0) and (S.Name <> '.') and
     (S.Name <> '..') then
     begin
     Item := TMenuItem.Create(Self);
     Item.Caption := S.Name;
     Root.Add(Item);
     BuildMenuTree(Path + S.Name, Item);
     end;
   Rslt := FindNext(S);
   end;
 SysUtils.FindClose(S);
end;
 
//Spustíš to takto:
 
 BuildMenuTree('C:\', Item);
 
//Item je item v menu