if FileExists(ExtractFilePath(Application.ExeName) + 'Help.hlp') then
ShellExecute(handle, 'open', Pchar(ExtractFilePath(Application.ExeName) + 'Help.hlp'), nil, nil, SW_SHOWNORMAL)
else
Application.MessageBox('未找到帮助文件!', '错误', MB_ICONINFORMATION);
注意:在uses中加入:shellapi