This article describes how to prevent Windows Messenger from running. By default, Windows XP Professional and Windows XP Home Edition install Windows Messenger. The user interface does not let you remove or uninstall Windows Messenger.

When you install Windows XP Service Pack 1 (SP1), Windows adds a new feature that is named "Set Program Access and Defaults" to the Add or Remove Programs tool in Control Panel. You can use this feature to remove Windows Messenger from the Start menu, from the desktop, or from other locations. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

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To prevent Windows Messenger from running, use the method appropriate for your version of Windows Messenger and your version of Windows.

•	Windows Messenger 4.0 or later versions on a Windows XP Professional-based computer
•	Windows Messenger 4.0 on a Windows XP Home Edition-based computer
•	Windows Messenger 4.5 or later versions on a Windows XP Home Edition-based computer or on a Windows XP Professional-based computer

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Windows Messenger 4.0 or later versions on a Windows XP Professional-based computer

Use the Group Policy (gpedit.msc) snap-in to turn on the Do not allow Windows Messenger to be run option.

Notes

•	To use the Group Policy snap-in, you must be logged on to the computer using an account that has administrator permissions.
•	This method prevents programs that use the Messenger APIs from using Windows Messenger. Microsoft Outlook 2002, Microsoft Outlook Express 6, and the Remote Assistance feature in Windows XP are examples of programs that use these APIs and that depend on Windows Messenger.

To turn on the Do not allow Windows Messenger to be run option, follow these steps:

1.	Click Start, click Run, type gpedit.msc, and then click OK.
2.	In Group Policy, expand Local Computer Policy, expand Computer Configuration, expand Administrative Templates, expand Windows Components, and then expand Windows Messenger.
3.	Double-click Do not allow Windows Messenger to be run, and then click Enabled.
4.	Click OK.
5.	On the File menu, click Exit to quit the Group Policy snap-in.

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Windows Messenger 4.0 on a Windows XP Home Edition-based computer

NOTE: This method does not prevent users from manually running Windows Messenger, but it does prevent Windows Messenger from running automatically every time that you start Windows.

Change the preferences in Windows Messenger. To do this, follow these steps.

1.	Start Windows Messenger.
2.	On the Tools menu, click Options, and then click the Preferences tab.
3.	Click to clear the Run this program when Windows starts check box, and then click OK.

If you use Outlook Express or Outlook 2002, Windows Messenger may start automatically every time that you run Outlook Express or Outlook. To prevent Windows Messenger from starting automatically, follow these steps:

Outlook Express

1.	On the Tools menu, click Options, and then click the General tab.
2.	Click to clear the Automatically log on to Windows Messenger check box, and then click OK.

Outlook 2002

1.	On the Tools menu, click Options, and then click the Other tab.
2.	Click to clear the Enable Instant Messaging in Microsoft Outlook check box, and then click OK.

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Windows Messenger 4.5 or later versions on a Windows XP Home Edition-based computer or on a Windows XP Professional-based computer

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

Note This method prevents programs that use the Messenger APIs from using Windows Messenger. Outlook 2002, Outlook Express 6, and the Remote Assistance feature in Windows XP are examples of programs that use these APIs and that depend on Windows Messenger.

1.	Start Registry Editor. To do this, click Start, click Run, type regedit.exe, and then click OK. If the following registry subkey already exists, go to step 6: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Messenger\Client
2.	Click the following registry subkey: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft
3.	On the Edit menu, point to New, and then click Key. Type Messenger for the name of the new registry key, and then press ENTER.
4.	Click the following registry subkey: key: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Messenger
5.	On the Edit menu, point to New, and then click Key. Type Client for the name of the new registry key, and then press ENTER.
6.	Click the following registry subkey: key: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Messenger\Client
7.	On the Edit menu, point to New, and then click DWORD Value. Type PreventRun for the name of the new DWORD value and then press ENTER.
8.	Right-click the PreventRun value that you created in step 7, and then click Modify. In theValue data box, type 1, and then click OK.
9.	Quit Registry Editor.

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