[pesi]

Код:

procedure TForm1.Button1Click(Sender: TObject);
var
  XL: Variant;
begin
try
  XL:= CreateOleObject('Excel.Application');
  XL.WorkBooks.Open(ExtractFilePath(Application.ExeName)+'1.xls');
  XL.Visible:= True;
  XL.ActiveWorkbook.ActiveSheet.ComboBox1.AddItem('bbb');
  XL.ActiveWorkbook.ActiveSheet.ComboBox1.AddItem('aaa');
  XL.ActiveWorkbook.ActiveSheet.ComboBox1.ListIndex:= 1;
except
  ShowMessage('Error, error, Error');
end;
end;