The following example demonstrates deleting all the files in a directory and then the directory itself. Additional processing would be required to delete read only files and files that are in use.

procedure TForm .Button Click(Sender: TObject);
var
  DirInfo: TSearchRec;
  r : Integer;
begin
  r := FindFirst('C:\Download\Test\*.*', FaAnyfile, DirInfo);
  while r = 0 do  begin
    if ((DirInfo.Attr and FaDirectory <> FaDirectory) and
        (DirInfo.Attr and FaVolumeId <> FaVolumeID)) then
      if DeleteFile(pChar('C:\Download\test\' + DirInfo.Name))
         = false then
       ShowMessage('Unable to delete : C:\Download\test\' +
                   DirInfo.Name);
    r := FindNext(DirInfo);
  end;
  SysUtils.FindClose(DirInfo);
  if RemoveDirectory('C:\Download\Test') = false then
    ShowMessage('Unable to delete direcotry : C:\Download\test');
end;