Complex sentence: Windows 8 introduces a new form of start menu called Start screen, which resembles the home screen of Windows Phone serves as the primary method of launching applications, and is shown in place of the desktop on startup.
Split into simpler sentences: Windows 8 introduces a new form of start menu called Start screen, which resembles the home screen of Windows Phone. This serves as the primary method of launching applications, and is shown in place of the desktop on startup.