Stop programs from starting up automatically on boot on Windows

To remove programs from the boot process, first check if it it in Start Menu > All Programs > Startup. If it is, remove it.

Next, go Start Menu > Run > msconfig. In the startup tab (I think it is the last tab), unchecked the program you wan to stop starting up. The names may not be the same to what you are used to, so you should check the Manufacturer and Command column to identify the correct programs to 'remove'. If it turns out you have removed the wrong program from the boot process, you can just go back into the msconfig utility and re-enable the program.

There are a few other ways apps can get started automatically - the easiest way to find/disable all of them is the autoruns utility

Don't forget to check a program's options or preferences. Some do have an option to start on windows start-up that you can disable but hide it well. If I remember right, Live Messenger's option was pretty well hidden, for example.