No need to edit registry or use any other softwares just 2 remove msn messenger ...
Just follow these simple steps ...
* Click ... start > run
* type gpedit.msc
* click ok ...
* This will open Group Policy Editor
* Browse to folder ...
* Computer configuration > Administrative Templates > Windows Components > Windows Messenger
* on Right panel u c 2 options ...
* By default it enabled ... R-click & disable it ...
Voila ...
Now MSN messenger won`t load in system tray after startup ...
For all other users perform all above steps bt browse folder "per user"
Above tutorial is from Microsoft.com ...
i have applied the above tut., it really boosted my startup by some sec. ...
Hope it helps U ...