List of features removed in Windows XP
As the next version of Windows NT after Windows 2000, as well as the successor to Windows Me, Windows XP introduced many new features but it also removed some others. Following is a list of these.

Shell
 The balloon notification that warns the users when removing external flash storage devices without safe unmounting has been removed.
 The Line Up Icons command on the desktop is no longer available. It is replaced by the Align to Grid option. Due to this being a toggle, simply aligning desktop icons once without further constraining their placement requires an extra click.
 The Minimize all windows command on the taskbar is hidden. The purported replacement, Show the desktop, co-existed with this feature on Windows 2000 and in any case only hides windows temporarily instead of actually minimizing them. It is still accessible through the  keyboard shortcut but it is not available through the mouse.
 The Show icons using all possible colors (which was previously introduced in Microsoft Plus! for Windows 95 and Windows NT 4.0) option in Display Properties is no longer available. Icons are always shown using all possible colors. Microsoft states that this is by design.
 The VGA screen resolution and 8-bit color depth options have been removed from the Settings tab of Display Properties. It is still possible to select these options using the Advanced button available under this tab, but Microsoft states that this workaround is unsupported.
 In the Command Prompt, QuickEdit mode and Insert mode are disabled by default.
 Links to Phone Dialer and NetMeeting were removed from the Start menu.

Boot 
 Boot screen progress bar is no longer determinate.

Personalization
 With the Desktop Themes utility in 2000 becoming the Themes tab in Display Properties in XP, the Rotate theme monthly option in Desktop Themes, which was introduced in Microsoft Plus! 98 and later included in Windows 2000, and both the options to select what parts of a theme to apply and the previews for parts of a theme were removed.
 The previous wallpapers and tiles from Windows 95-98, Windows Me, Windows NT 4.0 and Windows 2000 including the Plus! wallpaper were removed.
 The Utopia sound scheme, first included in Windows 95, was removed.
 It is no longer possible to save or delete schemes under the Appearance tab of Display Properties.
 The option to select a Pattern under the Background (9x/NT)/Desktop (XP) tab of Display Properties was removed.
 The 3D Maze (possibly due to the Windows logo having been changed, although the Wingdings font with the old Windows logo is still present) and Flying Windows screensavers were removed. The 3D Pipes teapot easter egg also no longer works on Windows XP.

Windows Explorer
 Small Icons view is no longer available in Windows Explorer.
 Web view in folders was disabled by default but can be reinstated by editing the registry. Additionally, the Customize This Folder Wizard was removed. Due to the removal of Web view, pie charts showing disk space are no longer available immediately upon opening a drive.
 The status bar no longer shows the free space remaining on the given disk when browsing through folder paths of shell namespace extensions, removable drives, and network shares when the navigation pane (Folders) in Windows Explorer is turned on, unlike in Windows 2000. It continues to show the free space remaining only for paths on local drives. In combination with the Web view-related lack of pie charts previously mentioned, this means it is no longer possible to immediately view the amount of space remaining in these three cases.
 The Directory icon was removed from My Network Places.
 The default sort order in Windows Explorer has changed but can be restored by editing the registry.

Bundled applications
 Deluxe CD Player, which was also first part of Microsoft Plus! 98 before being included in Windows 2000, was removed. Some functionality, including uploading and on-demand (as opposed to automatic) downloading of audio track information and track previewing was not available in the replacement, Windows Media Player.
 DVD Player is no longer usable as it is now a stub that simply opens Windows Media Player.
 Imaging for Windows was removed. It was replaced by the Windows Picture and Fax Viewer and Scanner and Camera Wizard but these two programs do not include some of its advanced functionality.

Protocols
 NetDDE and NetBEUI are no longer installed by default but can still be manually installed from the Windows XP CD-ROM.
 The DLC network protocol is no longer included. A download was made available by Microsoft.
 The AppleTalk protocol is no longer included.

Subsystems
 The Microsoft POSIX subsystem was removed. Windows Services for UNIX is available as a replacement.
 The Microsoft OS/2 subsystem was removed.

Hardware support
 Both graphical and command-line formatting options for floppy disks of capacities other than 1.44 MB were removed.
 Support for non-Plug and Play networking devices, such as modems and NICs, and native support for modems slower than 28.8 kbps was removed.
 A number of SCSI host adapters are no longer supported.
 Windows XP support for NEC's PC-98 series, the i486 Instruction Set and Silicon Graphics' Visual Workstation 320 and 540 was removed.
 New printer installations are required to use user-mode rendering components.

Windows 9x
 WebTV for Windows was removed and MSN TV can be installed manually.
 DriveSpace was removed in favour of native NTFS compression.
  The NTBackup tool included in Windows XP does not support certain backup formats available for use in the MSBackup tool in Windows 9x.
 A number of MS-DOS commands are no longer present on Windows XP.

Later versions

Service Pack 2
 The following raw socket functionality was removed: sending TCP network packets, sending UDP packets with invalid source network addresses, and associating local addresses.
 The number of TCP half-open connections was restricted.
 Program Manager was removed and replaced with Windows Explorer.
 Media Bar, which replaced the Radio Toolbar in Internet Explorer 6, was removed.
 Background message compaction was removed from Outlook Express. Outlook Express in Service Pack 2 automatically compacts messages every hundredth time it is run.
The original release of Windows XP came with unique boot screens that identified the edition of Windows XP currently running, including a green progress bar for Home Edition and a blue progress bar for Professional, Embedded, Tablet PC Edition, and Media Center Edition. These unique boot screens were removed in Service Pack 2 and replaced with a single generic "Windows XP" boot screen with a blue progress bar.

Service Pack 3
 The Address bar toolbar on the taskbar was removed for legal reasons, according to Microsoft. Windows Desktop Search is touted as a replacement.
 The option to display the special Internet Explorer icon on the desktop was removed.
 The ability to install service packs cumulatively is no longer available in Service Pack 3 as it requires at least Service Pack 1 to be installed first (Service Pack 2 in the cases of the original Windows XP Media Center Edition and Windows XP Media Center Edition 2003). Cumulative slipstreaming, however, is still possible and supported.
 The Energy Star logo in the Display Properties dialog, which originated in previous versions of Windows XP and included up to Service Pack 2, was removed.

Media Center Edition 2005
 Despite this edition being developed from Windows XP Professional, domain support is unavailable. Microsoft states that this is due to Windows Media Center Extenders requiring fast user switching. The exceptions to this are if it is selected during installation or already in use before an upgrade, but leaving the domain will still disable the feature.
 Windows Media Player 6.4, which was present in Windows 2000 and can be installed in Windows 95 and NT 4.0, was removed.

See also
 Windows Server 2003

References

Windows XP
Windows XP
Microsoft lists
Computing-related lists