http://en.wikipedia.org/wiki/List_of_features_removed_in_Windows_8
Windows 8 is the successor to Windows 7 in Microsoft's Windows line of operating systems. Several features which were present in Windows 7 are no longer present in Windows 8.
Aero Flip 3D has been removed. Win+Tab now activates an app switcher only for Metro-style apps.
The Start menu has been removed in favour of a full screen interface called the Start screen.[2]
Start screen lacks the global "Recent Documents" menu.[3]
Start screen lacks the automatically filling by usage tracking "Most Frequently Used" (MFU) programs list, each with its "Recent Documents" menu.[3][4]
The Aero Glass theme, which has been featured in Windows Vista and Windows 7 has been removed from Windows 8 in favour of a Metro-style theme.[5][6]
Windows Desktop Gadgets which has been featured in Windows Vista and Windows 7 has been removed from Windows 8. [7]
The User Log on/Log off sounds have been removed. The startup sound remains but is disabled by default.
Games such as Chess Titans have been removed. However some of them are now available on the Windows Store.
Networking
For dial-up connection (DUN), some of the options under Redialing options such as "Redial attempts" and "Redial if line is dropped" is no longer available. Although dial-up using PSTN telephone line is becoming increasingly rare, this could affect users that still use DUN to connect to 2G/3G/3.5G mobile network and also DSL subscribers that use Windows' PPPoE dialer.[9]
The Manage wireless networks under Network and Sharing Center is no longer available, although a similar function is still available through netsh command (netsh wlan).
Similarly, creating an ad-hoc wireless connection ("Set up a new connection or network" > "Set up a wireless ad hoc") is no longer available through the GUI; users need to use the same netsh command or third-party utility such as Connectify.
Media features
Windows Media Center will no longer be included by default in any version of Windows 8, but is available as a free add-on for Windows 8 Pro until 31 January 2013.[10][11]
Windows Media Player will no longer include codecs to play DVDs,[12] but DVDs will be playable if the Windows Media Center add-on is installed.[10]
Windows Media Center cannot run on start up or on top of other windows because of “new Windows OS requirements and behaviors”.[13][14]
Windows DVD Maker has been removed.
Standards compliance
The POSIX subsystem, SUA, has been deprecated and will be removed from the next release of Windows.[15]
Other
Backup and Restore has been renamed Windows 7 File Recovery in favor of the new feature called File History.[16]
The Blue Screen of Death no longer shows as much technical information about the error that caused the computer to stop.[17]
Windows CardSpace has been removed in favor of the new feature U-Prove.[18]
The Parental Controls feature present in earlier versions of Windows has been removed and replaced by the Family Safety feature.[19]
Chkdsk only shows a percentage when running at start up. [20]