Article: Several notable features have been removed in Windows 8, beginning with the traditional Start menu. Support for playing DVD-Video was removed from Windows Media Player due to the cost of licensing the necessary decoders (especially for devices which do not include optical disc drives at all) and the prevalence of online streaming services. For the same reasons, Windows Media Center is not included by default on Windows 8, but Windows Media Center and DVD playback support can be purchased in the "Pro Pack" (which upgrades the system to Windows 8 Pro) or "Media Center Pack" add-on for Windows 8 Pro. As with prior versions, third-party DVD player software can still be used to enable DVD playback.

Now answer this question: What does the Pro Pack do?
upgrades the system to Windows 8 Pro