ShellExecuteEx

var
  ExecInfo: TShellExecuteInfo;
begin
if FileExists(ExtractFilePath(ParamStr(0))+'document.doc') then begin
  ZeroMemory(@ExecInfo, sizeof(ExecInfo));
  with ExecInfo do
  begin
    cbSize := sizeOf(ExecInfo);
    fMask  := SEE_MASK_NOCLOSEPROCESS;
    lpVerb := PChar('open');
    lpFile := pchar(ExtractFilePath(ParamStr(0))+'document.doc');
    nShow  := 1;
  end;
  ShellExecuteEx(@ExecInfo);
  if ExecInfo.hInstApp<32
  then WaitForInputIdle(ExecInfo.hProcess, 10000) end else
ShowMessage('Файл отсутствует!');
end;