This tip works with Windows 2000 and XP using all versions of MSN Messenger.

MSN Messenger always loads automatically when visiting Hotmail and/or other related web sites.

But you can prevent this from happening by hacking the Registry.
Open Regedit and go to:

HKEY_CLASSES_ROOT\CLSID\{F3A614DC-ABE0-11d2-A441-00C04F795683}\LocalServer32

Start by backing up this Registry key, in case you want to reenable it for some reason in the future.

Delete the entire line which displays the path to MSMSGS.EXE from the “(Default)” String Value: double-click on it -> delete the entire Value data line -> click OK or hit Enter.
Close Regedit.

MSN Messenger will stop loading from now on.”

To prevent MSN Messenger from loading/running in Win2000/XP, run Regedit and go to:

HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Mes senger\Client

Create if not present or modify if present these two DWORD [REG_DWORD] Values in the right hand pane: right-click on an empty spot -> select New -> Key -> DWORD -> name them “PreventAutoRun” and “PreventRun” (don’t type the quotes) respectively -> right-click on each one and type 1 in the Decimal box -> click OK -> exit the Registry Editor.
These settings will take effect after the first reboot.

To stop MSN Messenger from loading automatically upon every WinXP startup: click the Start button -> click Run… -> type msconfig -> click OK or hit Enter -> click Startup tab -> remove the check mark next to Windows Messenger -> close Msconfig -> restart Windows.

Note that this way Messenger still loads when called upon by other apps like Outlook, Outlook Express or Hotmail (MSN) web access.

To stop MSN Messenger from loading automatically upon every WinXP startup: click the Start button -> click Run… -> type gpedit.msc (Group Policy Editor) -> click OK or hit Enter -> select Per Machine Restriction -> Computer Configuration -> Adminstrative Templates -> Windows Components -> Windows Messenger -> change from automatic to manual or disable it. Then: Per User Restriction -> User Configuration -> Adminstrative Templates -> Windows Components -> Windows Messenger -> change from automatic to manual or disable it -> exit GPE -> restart Windows.

In case after doing this Outlook or Outlook Express takes too long to open, you need to also:

MS Outlook Express -> Tools -> Options -> General tab -> turn off Messenger Support.

MS Outlook -> Tools -> Options -> Other -> turn off Messenger Support.

To prevent MSN Messenger from automatically signing in using a registered Microsoft Passport account: click the Start button -> click Run… -> type control userpasswords2 -> hit Enter or click OK -> click Advanced tab -> select Manage Passwords -> delete all Passport entries -> click OK/Apply.

Then run MSN Messenger -> sign in -> type your passport, e-mail address and password -> uncheck the “Sign me in automatically” box -> save your settings and close MSN Messenger.

“To permanently disable MSN Messenger when using Outlook (Express) or Hotmail web site, simply rename the C:\Program Files\Messenger folder to Messenger-OFF! (example).

This will effectively shut down Messenger, but not interfere with the loading of Outlook