I couldn’t find documentation on this elsewhere on the net so I decided to add a note here. I have to use a Windows XP workstation at my job and I’ve been annoyed that the Windows Live Messenger program seems to start up every time the system restarts. Disabling this was non-obvious:
Open Windows Live Messenger
Click on the question mark icon on the right hand side of the window.
From the popup menu choose Show the menu bar
In the menu bar (at the top of the window) click on Tools -> Options
Click on Sign In in the left hand side menu
Uncheck the checkbox that says Automatically run Windows Live Messenger when I log on to Windows
Click the OK button.
Quit the program