On Windows Vista when your pc starts Windows Live Messenger starts as well. Many of my clients do not like the fact that they have to close the window manually even though its really only one click to close the program.
In order to prevent Windows Live Messenger from running on login here is what I did.
Create a dummy(or an actual account if you use the software) and then login
to Live Messenger.
Under the menu choose Options. In that window you can disable the checkbox
that starts Windows Live Messenger at startup.
You can also unstall the software completly but if you ever plan to use it you would then have to reinstall it again. I have also not found any easy way to uninstall if from Vista anyway. Please post a comment if you have easily removed it from Vista.
This may not be the only way to fix this problem but It Fixed It for me.
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