When we use IE to log in to Hotmail, Spaces, or other online Windows Live services, the Messenger application automatically starts and logs in.
Windows Live Messenger (MSN): Download Link
In most cases, we don't want Messenger to start at this time, so we can prevent it from launching with the web page. Here's how:
1. Open IE, click on "Tools" -> "Manage Add-ons";
2. In the "Manage Add-ons" window that pops up, select "All Add-ons" in the "Show" section (in IE6/IE7, this is called "Add-ons that run without being requested");
3. Find the Windows Live project among them (if you're using an older version of Messenger, you might find a project named Windows Live Messenger), select them, and click "Disable".
After disabling this add-on, when you log in to web pages like Hotmail or Spaces using the IE browser in the future, Messenger will no longer start automatically. Actually, the real "culprit" is the item with the class ID {E1771B7F-98BE-407F-BA67-AA16ADA5D0C5}. However, since IE versions below IE8 cannot directly check the class ID of add-ons, you can disable all the Windows Live items you see. After disabling this add-on, besides Messenger no longer starting with Hotmail, Spaces, etc., there is a minor impact: the online services of Windows Live will not be able to display the status of Messenger contacts. But this should have little effect on our normal usage, right?