Digital Grabber explains how to clean up Windows Startup

Some of the kinder and well written programs are configurable and allow you to change the settings that starts them up. If this option is available, then this is the best approach. There are, however, many programs that do not give you the choice and no matter how many times you remove them, they return. Two that I find really annoying are the "Windows Messenger" and the "Quicktime Task". Both sit in the system tray and I don't need or want them there. I'll show you how to get rid of them forever if you have Windows XP Pro or Windows 2000. For those with Windows XP Home, this solution will not work.

How To Clean Up Windows Startup