You can't.
Although programs do exist that remove pieces of IE from windows, it is probably not a good idea to use them. Microsoft has "integrated" IE into the rest of their OS, so you can not get rid of IE without breaking a great deal of other components. Besides, you'll need it to use windows update.
Just install firefox. It will ask you if you want it to be your default browser. If you say "yes" it will supplant internet explorer in many areas.
~psi42